[MPS] Fix build regressions introduced by #92868 (#101036)
https://github.com/pytorch/pytorch/pull/92868 introduced `OBJC` and `OBJCXX` language dialects, but fails to propagate some important flags, like OpenMP include path(if found), `-fno-objc-arc` and `-Wno-unguarded-availability-new` suppression.
This PR remedies that and fixes https://github.com/pytorch/pytorch/issues/100925
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### <samp>🤖 Generated by Copilot at 62677d4</samp>
This pull request improves the support for MPSGraph on Apple platforms by fixing some CMake flags for parallelism and memory management. It modifies `cmake/Dependencies.cmake` and `CMakeLists.txt` accordingly.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/101036
Approved by: https://github.com/atalman, https://github.com/huydhn
