Add conda env to path in NB-04 image

[sjspielman]

This PR is my version of #1311 for the cell-type-neuroblastoma-04 module, after getting the error below when testing.

Command error:
  2:44PM INF instance metadata ami-id=ami-0ed843a06c28c7dfe instance-id=i-07b06054a1e7cd7d0 instance-type=m6a.4xlarge
  Traceback (most recent call last):
    File "/usr/bin/train-scanvi-model.py", line 11, in <module>
      import anndata
  ModuleNotFoundError: No module named 'anndata'

[allyhawkins]

🐱