Indexes are rebuilt when changes to the Search Index Manager Options are saved

Reproduction steps:
1. Open the attached “Quick Search Test 2.zip“ project
2. Open Window > Search > Index Manager, select the Keywords tab and find the “t:weapon” keyword
3. Open Window > Search > New Window and type in “t:weapon” in the search bar and look at the results
4. Open the “CustomPrefabIndexer.cs” Script and comment out the 10-33 lines
5. Enable Properties in the Options dropdown of the Search Index Manager window and press the “Save” button
6. Observe the Search window and Keywords tab of the Search Index Manager

Expected result: The “t:weapon” keyword exists and typing it into the Search window shows the results
Actual result: The “t:weapon” keyword doesn’t exist and typing it into the Search window shows no results

Reproducible with: 2021.3.25f1, 2022.2.20f1, 2023.1.0b16, 2023.2.0a15
Could not test with: 2020.3.48f1 (Errors in the console)

Reproduced on: macOS Monterey 12.6 (Intel), Windows 10 (by the reporter)