unyt md5 error

On Pleiades, I encountered this strange error:

```python
>>> import yt
File "/home1/hzhou4/swbuild/Python-3.12.10/lib/python3.12/site-packages/unyt/unit_registry.py", line 96, in unit_system_id
m = md5()
^^^^^
ValueError: [digital envelope routines: EVP_DigestInit_ex] disabled for FIPS
```

This appears to be common among tools that use hashlib. The following workaround seems to fix the problem, edit
```python
hasher = hashlib.md5(usedforsecurity=False)
```

I submited an issue to unyt: https://github.com/yt-project/unyt/issues/580

Start by reproducing the reported `import yt` failure on Pleiades with FIPS enabled and inspect the installed `unyt/unit_registry.py` at the reported `unit_system_id` location. Read the linked unyt issue for context, then determine whether flekspy owns the affected integration; done means the import no longer raises the FIPS-related md5 error.

Written by the indexing model from the issue text.