Test error occasionally

[jonhealy1]

This test seems to fail occasionally - maybe 5% of the time:

=========================== short test summary info ============================
FAILED stac_fastapi/tests/extensions/test_aggregation.py::test_post_aggregate_total_count - assert 2 == 1

[jamesfisher-geo]

I am not able to reproduce the error locally, but I have also noticed the issue when testing is run on github. My best guess is that it is an issue with async tests running in parallel.

[jonhealy1]

I think we can close this now?

[jamesfisher-geo]

Yup. Fixed in #314