Modernbert fixes (#38912)
* Removed deprecated argument in modernbert RotaryEmbedding
* Skip test_sdpa_can_dispatch_on_flash for modernbert
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Co-authored-by: ivarflakstad <69173633+ivarflakstad@users.noreply.github.com>
Co-authored-by: Yih-Dar <2521628+ydshieh@users.noreply.github.com>
