Fix mps unary op issue on non densely stored tensors (#105512)
This pr fixes a bug where non densely stored tensors were not converted to the dense tensors of the correct scalar type in the mps `unary_op` helper function
Fixes https://github.com/pytorch/pytorch/issues/105284
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105512
Approved by: https://github.com/malfet
