Fix usage of additional kwargs in `from_encoder_decoder_pretrained` in encoder-decoder models
# What does this PR do?

Somewhat continuing https://github.com/huggingface/transformers/pull/15043 but concerning all of the encoder-decoder models:
If, like in this [example](https://github.com/huggingface/transformers/blob/f71fb5c36e739d8224419bb091b4c16531df829f/examples/pytorch/speech-recognition/README.md?plain=1#L218), extra keyword arguments are used with `from_encoder_decoder_pretrained` it raises an error:
```pthon
TypeError: __init__() got an unexpected keyword argument 'add_adapter'
```
This is because the arguments [should be part of the config](https://github.com/huggingface/transformers/blob/f71fb5c36e739d8224419bb091b4c16531df829f/src/transformers/models/auto/auto_factory.py#L136).

This PR tries to fix this issue.


## Before submitting
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      Pull Request section?
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- [ ] Did you write any new necessary tests?


## Who can review?

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@patrickvonplaten

Hey @jsnfly,

sorry for answering so late. Great job on identifying the problem! I left some improvements as comments in the PR. The problem is that if we remove `**kwargs_encoder` from `AutoModel.from_pretrained(...)` we loose functionality - *e.g.* if someone would pass `local_files_only=True`. 

Could you maybe adapt all examples as shown for `EncoderDecoderModel` above? :-) Think then we can merge this one!<|||||>Hey @patrickvonplaten,

thank you for the suggestions, they do indeed make the code a lot cleaner and more functional! Let me know if there are additional improvements.<|||||>> indeed

Great job @jsnfly! Checked it locally and everything works perfectly fine :-) 

<|||||>Great job merging this PR! the documentation will now be removed from the staging environment.