conda_test job randomly fails about 50% of the time

The conda_test CI job fails about half of the time. It can be manually retried.

E.g. https://gitlab.astro-wise.org/micado/micadowise/-/jobs/15646 had to be ran three times before it succeeded.

All logs of failed jobs have the following line, which is not present in the logs of passed jobs:

/usr/bin/env: python: Invalid argument

The line can be in different locations, so maybe there is some race condition going on somewhere.

@teake can you think of any reason these jobs fail?