metal: add GATED_LINEAR_ATTN support

[Ra5hidIslam]

Overview

Added Gated Linear Attention Op for Metal

Additional information

Passed all the tests, no performance test was there so couldn't test the performance.

Related to #14909

Requirements

• I have read and agree with the contributing guidelines
• AI usage disclosure: Yes, in understanding the code, all code and logic has been written by me.

[TheTom]

Hey @Ra5hidIslam, nice work on this! Just wanted to flag that I have an existing PR for the same op over at #21452, filed April 5. It covers head_size 64 and 128, includes test-backend-ops updates, and regenerates the docs. Might be worth consolidating so we're not duplicating effort. Happy to collaborate if you want to combine forces!

[Ra5hidIslam]

Hey @Ra5hidIslam, nice work on this! Just wanted to flag that I have an existing PR for the same op over at #21452, filed April 5. It covers head_size 64 and 128, includes test-backend-ops updates, and regenerates the docs. Might be worth consolidating so we're not duplicating effort. Happy to collaborate if you want to combine forces!

Thanks for the heads up, didn't see #21452 when I started. Your PR is further along (both head sizes + tests + docs), so it makes sense to consolidate there. Happy to review it and contribute anything useful from my implementation. Closing this one.

[Ra5hidIslam]

Closing this one, as there is a prior PR with #21452 which is doing the same.