[MPS] Fix the crash in huberloss with Float16 (#94567)
- Also fix FP16 correctness issues in several other ops by lowering their FP16 precision in the new list `FP16_LOW_PRECISION_LIST`.
- Add atol/rtol to the `AssertEqual()` of Gradient tests.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94567
Approved by: https://github.com/kulinseth
