[Model] Merged multimodal processor for Paligemma

[kylehh]

1. Created merged MM processor for Paligemma
2. Issue to be solved:
   • need newline at prompt (solved by overriding BaseMultiModalProcessor.apply())
   • paligemma 2 support (solved by adding <bos> token)

[github-actions]

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[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @kylehh.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[kylehh]

Newline issue is solved by overriding _apply_prompt_replacements

[kylehh]

paligemma2 is not adding "<bos>" token according to tokenizer config ( compare to paligemma's config here)
So add bos token to adapt with prompt replacment

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @kylehh.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[DarkLight1337]

Please remember to test this by adding the model to tests/models/multimodal/processing/test_common.py

[DarkLight1337]

Thanks for your hard work!

[DarkLight1337]

Can you fix the merge conflicts?

[DarkLight1337]

It looks like the model isn't outputting Spanish correctly.

[kylehh]

continue work in #14015 to update code w PromptUpdate