I-ALiRT - check coverage

[laspsandoval]

This pull request removes the parse_uksa_schedule_xlsx function and its associated tests from the codebase, as well as some unused imports. The changes help to simplify the generate_coverage.py module and its test suite by eliminating code that is no longer needed.

Code cleanup and simplification:

• Removed the parse_uksa_schedule_xlsx function from generate_coverage.py, including all related logic for parsing UKSA (GHY-6) availability sheets.
• Deleted all tests related to parse_uksa_schedule_xlsx from the test file test_generate_coverage.py, including both unit tests and integration tests that used this function.
• Removed the import of parse_uksa_schedule_xlsx from the test file test_generate_coverage.py.
• Cleaned up unused imports (Path and pandas as pd) from generate_coverage.py.

Data update:

• Added "DSS-43" to the list of station names in generate_coverage.py.

Note: Originally this PR was intended to fix any differences between the predicted ephemeris kernel and the actual packet ingest timeframes. But after some analysis it was determined that most likely the recent predicted ephemeris is less accurate due to possible recent maneuvers.

│ Date │ Kernel era │ Start error │ End error │
│ 2026-03-12 │ March kernel │ +4 min │ -1 min │
│ 2026-04-04 │ od028 (Apr 3+) │ +18 min │ -15 min │

[lacoak21]

Nice! So clean 😍