Update git submodules
- Update extensions/WikimediaEvents from branch 'wmf/1.30.0-wmf.19'
- Turn off human search relevance survey
The survey has run for two weeks. Turn off now so we can analyze the results.
Bug: T175047 Change-Id: I1b758d5bf81acbd04243a5fe1954f86ae4cb4322 (cherry picked from commit 80f389f6223d115b6f84d2be0d146f07554df7bd)
- Turn off human search relevance survey