Search backend: remove query from RepoOptions
Created by: camdencheek
We currently hold a reference to the query in RepoOptions so we can determine whether fork and archived were set explicitly by the user, or whether we used defaults for those values. However, since we only need to know whether they were set explicitly, we can store that instead and reduce the scope of RepoOptions.
Stacked on #34129
Test plan
Checked changed tests and manually verified that excluded repos still show up in the UI as expected.