Refactor test_validate_override_fixes to be a unit test

[katie-lamb]

As was pointed out in #3251 , currently test_validate_override_fixes is an integration test for the FERC to EIA entity matching module that tests the functionality of validate_override_fixes. The test has parameters with record IDs that need to be updated annually to ensure that those records are from report years that are processed in the fast ETL. The test uses the FERC to EIA training data within validate_override_fixes.

Instead, this test should be refactored to be a unit test that takes synthetic training data that is passed into validate_override_fixes. Additionally, instead of XFAIL-ing, the tests should pass if an expected exception is raised or failure condition is observed. Finally, validate_override_fixes shouldn't allow duplicate FERC IDs to be matched to different EIA records after the overrides are complete. There are test parameters set up to test this, but the validate_override_fixes function won't actually catch that condition in it's current state.

• Refactor test_validate_override_fixes to be a unit test that uses synthetic FERC to EIA training data
• Change XFAIL-ing tests to tests that pass if an expected exception is raised
• Add a check in pudl.analysis.record_linkage.eia_ferc1_record_linkage.validate_override_fixes to make sure that there aren't duplicate FERC1 IDs matched to EIA records.