Add SDPA support for LayoutLMv3 model

[stancld]

What does this PR do?

Part of #35467.

Performance benchmark

Speed & memory req consumption on a token classification ntraining of LayoutLMv3-like model with multilingual support, various auxiliary tasks, masked language modelling.

GPU: 1x A100 80 GB
Batch size: 16, Accumulated gradient batches: 8

Impl.	Speed	Peak memory
Eager	~2.0 it/s	66.7 Gi
SDPA	~3.0 it/s	47.2 Gi

Overall, ~50% speed-up and memory reqs reduction is observed.

Before submitting

• Did you read the contributor guideline,
  Pull Request section?
• Was this discussed/approved via a Github issue or the forum? Please add a link
  to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

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.

cc: @ArthurZucker