Search backend: Rename `repos.ComputeExcludedRepos` to `repos.ComputeExcludedReposJob`
Created by: tbliu98
Stacked on https://github.com/sourcegraph/sourcegraph/pull/34863 Related to #34009 (closed)
Because repos.ComputeExcludedRepos
implements job.Job
, renaming repos.ComputeExcludedRepos
to repos.ComputeExcludedReposJob
for clarity when reading the code and looking at traces.
Test plan
Semantics-preserving.