Fix - Flaky QueryBuilder tests (#38860) (#38945)

* Use fetchMock.flush() to prevent tests from interfering with each other

* Revert "Use fetchMock.flush() to prevent tests from interfering with each other"

This reverts commit 03f1277cf2bf481ac36db212e15b4f29511a386b.

* Add typing for requests in the redux store

* Fix QueryBuilder flakes by introducing waitForLoadingRequests

* Simplify interface

* Add mocks for requests in redux store, update types

* Simplify code

* Increase timeout

Co-authored-by: Kamil Mielnik <kamil@kamilmielnik.com>