HOTFIX for issue #2048

[debora-pe]

As title, this PR fixes an issue identified by a user in the use of the spat_order in the wavetilts calibration. See #2048

Added a test in the Dev Suite, see and review: pypeit/PypeIt-development-suite#386

I tested on a magellan_fire echelle dataset, but I'll run the full tests.

[kbwestfall]

I think this looks good, but I admit it's a bit hard to follow.

Approving now, but we should wait to merge until the test results are in.

[debora-pe]

Tests pass!
The one failed vet test (test_scripts.py::test_identify - AssertionError: Bad auto ID) is the usual ghost in my machine.

Test Summary
--------------------------------------------------------
--- PYTEST PYPEIT UNIT TESTS PASSED  281 passed, 447 warnings in 342.79s (0:05:42) ---
--- PYTEST UNIT TESTS PASSED  158 passed, 93407 warnings in 1113.54s (0:18:33) ---
--- PYTEST VET TESTS FAILED  1 failed, 72 passed, 112911 warnings in 6385.97s (1:46:25) ---
--- PYPEIT DEVELOPMENT SUITE PASSED 291/291 TESTS  ---
Total disk usage: 228.297 GiB
Testing Started at 2026-01-20T15:05:07.119063
Testing Completed at 2026-01-21T11:47:09.628661
Total Time: 20:42:02.509598