Fix error message and add extension fallback
Fix the error message raised if `infered_module_name` is `None` in `CommunityDatasetModuleFactoryWithoutScript.get_module` and make `infer_module_for_data_files` more robust. 

In the linked issue, `infer_module_for_data_files` returns `None` because `json` is the second most common extension due to the suffix ordering. Now,  we go from the most common to the least common extension and try to map it or return `None`.

Fix #3331