Update pinned optimum-executorch commit hash in the CI (#9653)

Previous attempt to bump HF transformers version to latest is reverted
due to llava model imcompatibility. This PR is to just ensure the CI are
able to test `optimum-executorch` with latest version of HF transformers
and upcoming `executorch==0.6.0`.

Note: This change is purely on CI and only for optimum-executorch,
should not affect other models like llava.

Co-authored-by: Guang Yang <guangyang@fb.com>