Add QAIRT MHA2SHA transformation support

[qti-kromero]

Describe your changes

• Add MHA2SHA pass for QAIRT SDK that enables better performance on Qualcomm NPU

Checklist before requesting a review

• Add unit tests for this change.
• Make sure all tests can pass.
• Update documents if necessary.
• Lint and apply fixes to your code by running lintrunner -a
• Is this a user-facing change? If yes, give a description of this change to be included in the release notes.
• Is this PR including examples changes? If yes, please remember to update example documentation in a follow-up PR.