Return an error from project index tool when embedding query fails (#11264)

Previously, a failure to embed the search query (due to a rate limit
error) would appear the same as if there were no results.

* Avoid repeatedly embedding the search query for each worktree
* Unify tasks for searching all worktree

Release Notes:

- N/A
5831d80f51Max Brunsfeld committed on 5/1/2024, 7:15:44 PM· committed by GitHubparent4b76769
4 files changedLine totals unavailable