Backend tests and lint checks are failing in develop

[nikhil.agarwal.2019]

Hi oppia-devs,
I want to state that changes in develop due to #13065 causes some lint checks and backend tests to fail because of race condition for some handlers.
The pr is attempting to fix the issue: #13264.

Please update your branch with upstream/develop after the PR is merged.

[Sandeep Dubey]

Hi all,

FYI, #13264 is merged and the backend/lint tests are now fixed, please update your PR with upstream/develop!

Thanks,
Sandeep