[MPS] Support for median with dim (#88807)
## Summary ⚡
**Aim**: Add support for aten::median for MPS backend (Fixes #87220)
This is fresh clean PR from the previous [PR](https://github.com/pytorch/pytorch/pull/88554)
- Implementing the new median function in aten/src/ATen/native/mps/operations/ReduceOps.mm
- Adding it to aten/src/ATen/native/native_functions.yaml
- Adding it to existing test_median
### **this will works like this** 🪶
median of entire input tensor on MPS
`torch.median(mps_inputTensor)`
median of along a dim
`torch.median(mps_inputTensor, dim=[int], keepdim=[Bool])`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88807
Approved by: https://github.com/kulinseth
