[mxfp8 moe training] Add mxfp8 to FSDP and TP tests

[danielvegamyhre]

Currently we have basic mxfp8 forward + backward supported in tochao scaled_grouped_mm with dynamic mxfp8 quantization: https://github.com/pytorch/ao/blob/main/test/prototype/moe_training/test_fsdp.py#L86

We need to add MXFP8 to these tests.