Fix unit tests with psi4

[j-wags]

Todos

Notable points that this PR has either accomplished or will accomplish.

• Fix CI is (reliably) failing #392
• I do not plan to update the feedstock, since psi4 isn't a hard dep, and folks already had workarounds to get valid psi4+libint2 combos
• No releasenotes update as this is not user facing

Status

• Ready to go

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.51%. Comparing base (f9b0d3f) to head (73d384f).

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• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[mattwthompson]

Great, I hoped it was going to be a relatively simple (in LOC, not necessarily complexity) change