Lock cache file of HF model list (#6628)
The error in the following log suggests that the cache file for HF model
list can be broken:
https://github.com/microsoft/DeepSpeed/actions/runs/11343665365/job/31546708118?pr=6614
The actual cause of the above error is unclear, but `_hf_model_list`
potentially breaks the cache file when it is concurrently called from
multiple processes. This PR locks the cache file to ensure
`_hf_model_list` safely reads and writes the file.
