Update no trainer examples for QA and Semantic Segmentation
Author: kiansierra
Pull request: yes

# What does this PR do?
Update run_qa_no_trainer.py, run_qa_beam_search_no_trainer.py,  run_semantic_segmentation_no_trainer.py examples to include `accelarator.gather_metrics`

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Fixes # https://github.com/huggingface/transformers/issues/18437


## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
- [X] Did you read the [contributor guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      Pull Request section?
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      to it if that's the case.
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- [ ] Did you write any new necessary tests?

I ran the scripts locally with the following arguments
```
  "program": "examples/pytorch/question-answering/run_qa_no_trainer.py",
  "args": [
      "--dataset_name",
      "squad",
      "--dataset_config_name",
      "plain_text",
      "--model_type",
      "bert",
      "--tokenizer_name",
      "bert-base-uncased",
      "--max_train_steps",
      "50"
  ]
```
```
    "program": "examples/pytorch/question-answering/run_qa_beam_search_no_trainer.py",
    "args": [
        "--dataset_name",
        "squad",
        "--model_name_or_path",
        "xlnet-base-cased",
        "--max_train_steps",
        "50"
    ]
```
```
    "program": "examples/pytorch/semantic-segmentation/run_semantic_segmentation_no_trainer.py",
    "args": [
        "--max_train_steps",
        "50"
    ]
```

## Who can review?
@muellerzr , @sgugger , @pacman100 
Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

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Library:

- benchmarks: @patrickvonplaten
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Documentation: @sgugger

HF projects:

- datasets: [different repo](https://github.com/huggingface/datasets)
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Comments:
_The documentation is not available anymore as the PR was closed or merged._