[MMS] Fix mms
Author: patrickvonplaten
Pull request: yes

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Fixes #25260.

The problem is that the model state_dict is retrieved before the weights are tied which in the case of MMS/Wav2Vec2 means before the state dict is rewritten to the correct expected structure since MMS/Wav2Vec2 loads adapter weights when modeling_utils calls `tie_weights`.

I'm not 100% sure if the moving `model.tie_weights()` up here a couple of lines is ok, but it's necessary to fix MMS.
I'm pretty sure it's fine because `tie_weights` should not fundamentally change the state_dict architectures for models != MMS.

I'm not able to fully pinpoint the reason for how this bug came to be, but as stated in #25260 loading MMS 
worked on the PR and without having `accelerate` installed it also worked on the main.

There were a couple of PRs that touched similar logic around at the same time or a bit later/sooner which might have caused the issue.

- https://github.com/huggingface/transformers/pull/24200
- https://github.com/huggingface/transformers/pull/24505
- https://github.com/huggingface/transformers/pull/24310

I might have accidentally also not synced my PR branch with "main" before merging so that between starting to work on it and merging a different logic creeped in.

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Comments:
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@ydshieh ok to merge or should we run some more tests?

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