Fix test failure in tor_dirmgr::state::test::get_microdescs_state

This failure occurred because our tests use canned data to exercise
the directory state functionality, and the canned consensus has
suddenly become very expired.

There are better fixes possible, but this is a minimal one that
should get CI working on main again.
6 jobs for dirmgr_state_test_fix in 19 minutes and 24 seconds