e2tomogram_refine.py  requires flax module

Hello, 

FIY 

```
rpmmaker [rpm]:EMAN2/2.99.70 > e2tomogram_refine.py --help
e2tomogram_refine.py --help
Traceback (most recent call last):
  File "/opt/miniforge3/envs/eman2/bin/e2tomogram_refine.py", line 13, in <module>
    from flax import nnx
ModuleNotFoundError: No module named 'flax'
```

maybee add this requirement in doc

regards

Eric