Fix infer module for uppercase extensions

Fix the `infer_module_for_data_files` and `infer_module_for_data_files_in_archives` functions when passed a data file name with uppercase extension, e.g. `filename.TXT`.

Before, `None` module was returned.

Comments:
_The documentation is not available anymore as the PR was closed or merged._

<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.007049 / 0.011353 (-0.004304) | 0.005034 / 0.011008 (-0.005974) | 0.097737 / 0.038508 (0.059229) | 0.033280 / 0.023109 (0.010170) | 0.301017 / 0.275898 (0.025119) | 0.336593 / 0.323480 (0.013113) | 0.005567 / 0.007986 (-0.002419) | 0.005384 / 0.004328 (0.001056) | 0.072980 / 0.004250 (0.068730) | 0.045030 / 0.037052 (0.007978) | 0.303280 / 0.258489 (0.044791) | 0.367528 / 0.293841 (0.073687) | 0.034131 / 0.128546 (-0.094415) | 0.012118 / 0.075646 (-0.063528) | 0.331677 / 0.419271 (-0.087594) | 0.049211 / 0.043533 (0.005678) | 0.297535 / 0.255139 (0.042396) | 0.318136 / 0.283200 (0.034936) | 0.101574 / 0.141683 (-0.040109) | 1.472769 / 1.452155 (0.020615) | 1.541724 / 1.492716 (0.049007) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.014646 / 0.018006 (-0.003360) | 0.439050 / 0.000490 (0.438560) | 0.008575 / 0.000200 (0.008375) | 0.000297 / 0.000054 (0.000242) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.027591 / 0.037411 (-0.009820) | 0.111639 / 0.014526 (0.097113) | 0.117098 / 0.176557 (-0.059458) | 0.173281 / 0.737135 (-0.563855) | 0.123197 / 0.296338 (-0.173141) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.397507 / 0.215209 (0.182298) | 3.971457 / 2.077655 (1.893803) | 1.781158 / 1.504120 (0.277038) | 1.590419 / 1.541195 (0.049224) | 1.716374 / 1.468490 (0.247884) | 0.687150 / 4.584777 (-3.897627) | 3.691009 / 3.745712 (-0.054703) | 2.050900 / 5.269862 (-3.218961) | 1.304893 / 4.565676 (-3.260784) | 0.084507 / 0.424275 (-0.339768) | 0.012231 / 0.007607 (0.004624) | 0.493033 / 0.226044 (0.266988) | 4.929957 / 2.268929 (2.661028) | 2.209069 / 55.444624 (-53.235555) | 1.885992 / 6.876477 (-4.990485) | 2.007004 / 2.142072 (-0.135069) | 0.827265 / 4.805227 (-3.977963) | 0.168225 / 6.500664 (-6.332439) | 0.064988 / 0.075469 (-0.010481) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.182341 / 1.841788 (-0.659447) | 14.691983 / 8.074308 (6.617674) | 14.350720 / 10.191392 (4.159328) | 0.164307 / 0.680424 (-0.516117) | 0.017480 / 0.534201 (-0.516720) | 0.421843 / 0.579283 (-0.157441) | 0.417481 / 0.434364 (-0.016883) | 0.496587 / 0.540337 (-0.043751) | 0.581208 / 1.386936 (-0.805728) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.007070 / 0.011353 (-0.004283) | 0.005083 / 0.011008 (-0.005926) | 0.075009 / 0.038508 (0.036500) | 0.032343 / 0.023109 (0.009234) | 0.366788 / 0.275898 (0.090890) | 0.392273 / 0.323480 (0.068794) | 0.005512 / 0.007986 (-0.002474) | 0.003999 / 0.004328 (-0.000329) | 0.073743 / 0.004250 (0.069492) | 0.046203 / 0.037052 (0.009151) | 0.367874 / 0.258489 (0.109385) | 0.409154 / 0.293841 (0.115313) | 0.035227 / 0.128546 (-0.093319) | 0.012223 / 0.075646 (-0.063424) | 0.087149 / 0.419271 (-0.332122) | 0.045648 / 0.043533 (0.002115) | 0.362414 / 0.255139 (0.107275) | 0.379970 / 0.283200 (0.096770) | 0.100631 / 0.141683 (-0.041052) | 1.439733 / 1.452155 (-0.012422) | 1.506266 / 1.492716 (0.013550) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.227071 / 0.018006 (0.209065) | 0.451243 / 0.000490 (0.450753) | 0.000406 / 0.000200 (0.000206) | 0.000060 / 0.000054 (0.000006) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.028952 / 0.037411 (-0.008459) | 0.111934 / 0.014526 (0.097408) | 0.124080 / 0.176557 (-0.052477) | 0.174022 / 0.737135 (-0.563113) | 0.126811 / 0.296338 (-0.169527) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.436423 / 0.215209 (0.221214) | 4.331959 / 2.077655 (2.254304) | 2.111914 / 1.504120 (0.607794) | 1.921338 / 1.541195 (0.380143) | 1.994425 / 1.468490 (0.525935) | 0.699164 / 4.584777 (-3.885613) | 3.722143 / 3.745712 (-0.023569) | 3.516538 / 5.269862 (-1.753323) | 1.867245 / 4.565676 (-2.698431) | 0.085923 / 0.424275 (-0.338352) | 0.012059 / 0.007607 (0.004452) | 0.586147 / 0.226044 (0.360102) | 5.395823 / 2.268929 (3.126894) | 2.594430 / 55.444624 (-52.850194) | 2.275021 / 6.876477 (-4.601456) | 2.347810 / 2.142072 (0.205737) | 0.835118 / 4.805227 (-3.970109) | 0.167089 / 6.500664 (-6.333575) | 0.064893 / 0.075469 (-0.010576) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.291423 / 1.841788 (-0.550365) | 14.992696 / 8.074308 (6.918388) | 13.307842 / 10.191392 (3.116450) | 0.163799 / 0.680424 (-0.516625) | 0.017315 / 0.534201 (-0.516886) | 0.461319 / 0.579283 (-0.117965) | 0.430474 / 0.434364 (-0.003889) | 0.568115 / 0.540337 (0.027777) | 0.647909 / 1.386936 (-0.739027) |

</details>
</details>

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