Add a unit test for switch of a profile state to pending

[jhrozek]

Summary

We recently suspected that one of our stored procedures is not behaving
as it should. This turned out to be false, but during debugging of the
stored procedure I already wrote a unit test for the behaviour that was
not working at the moment.

It makes sense to submit it in case we regress in the future.

Change Type

Mark the type of change your PR introduces:

• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

run the test

Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[coveralls]

coverage: 48.335%. remained the same
when pulling 0e034f9 on jhrozek:stored_procedure_test_for_pending
into deefb74 on stacklok:main.