It looks like we landed `collectSourceIndicesFromThreads` even though we removed the uses of it. Let's remove it. ┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-1328)
It looks like we landed
collectSourceIndicesFromThreadseven though we removed the uses of it. Let's remove it.┆Issue is synchronized with this Jira Task