Fix missing initializations for models created in 2023
Author: bvantuan
Pull request: yes

# What does this PR do?

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Fixes missing weight initializations for models created in 2023.

## Who can review?

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.
@Cyrilvallez 

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Comments:
cc @Cyrilvallez as we are also working on putting the default in the PreTrainedModel

Super happy to see you're following again on a new batch of models @bvantuan! 🚀🤗 Let me know when this is ready!

Yes, of course! Really excited to keep contributing whenever I have time.

Cc @Cyrilvallez ! The PR is now ready and awaiting your review😊.

Thanks a lot for reviewing, @Cyrilvallez ! I’m really glad you’re happy with it. I completely agree—using `normal_` instead of `copy_(torch.randn(...))` is much cleaner and more elegant. I’ve simplified that part and addressed the other comments as well.

**[For maintainers]** Suggested jobs to run (before merge)

run-slow: align, autoformer, bridgetower, bros, clap, clvp, efficientnet, fastspeech2_conformer, informer, kosmos2, mgp_str, mobilevit, mobilevitv2, mra, nllb_moe, omdet_turbo

Hi @bvantuan 

Thanks for the PR. Could you check

```
    "models_fastspeech2_conformer": {
        "job_link": "https://github.com/huggingface/transformers/actions/runs/16433389284/job/46439076372",
        "single": [
            {
                "line": "tests/models/fastspeech2_conformer/test_modeling_fastspeech2_conformer.py::FastSpeech2ConformerModelTest::test_can_init_all_missing_weights",
                "trace": "(line 687)  AssertionError: False is not true : The following keys are not properly handled by `_init_weights()`:"
            },
            {
                "line": "tests/models/fastspeech2_conformer/test_modeling_fastspeech2_conformer.py::FastSpeech2ConformerWithHifiGanTest::test_can_init_all_missing_weights",
                "trace": "(line 687)  AssertionError: False is not true : The following keys are not properly handled by `_init_weights()`:"
            }
        ]
    },
```
which are skipped before this PR but now failing since this PR? 


Hi @ydshieh @Cyrilvallez ! I think the `FastSpeech2Conformer` tests require `@require_torch_accelerator`, which might explain why they didn’t run on this CI. I opened a PR #39689 to fix this.

Indeed @bvantuan, the tests should not have that decorator as it prevents them being run by the CI! Thanks @ydshieh for raising the issue, the PR linked by @bvantuan will fix it! 🤗 I'm reactivating the tests as well!