Fix tests in #1108

[dhruvkb]

Description

This PR targets #1108 and updates the create_filtered_index function to refresh the index before sending the callback.

I don't fully grasp the mechanics of the process but that was what fixed the test failures for the main index generation too.

Checklist

• [x] My pull request has a descriptive title (not a vague title like Update index.md).
• [x] My pull request targets the default branch of the repository (main) or a parent feature branch.
• [x] My commit messages follow [best practices][best_practices].
• [x] My code follows the established code style of the repository.
• [x] I added or updated tests for the changes I made (if applicable).
• [x] I added or updated documentation (if applicable).
• [x] I tried running the project locally and verified that there are no visible errors.

[best_practices]: https://git-scm.com/book/en/v2/Distributed-Git-Contributing-to-a-Project#_commit_guidelines

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[dhruvkb]

Changes incorporated in #1108.