[Oppia Android] Oppiabot did not close a PR that was force pushed

[BenHenning]

Describe the bug
See oppia/oppia-android#3952. The author force-pushed their branch, but Oppiabot didn't detect & close it. Is there a specific feature that needs to be enabled for Oppia Android to make sure this works?

To Reproduce
Steps to reproduce the behavior: Unknown; I didn't try to repro it. Presumably any force push should demonstrate that Oppiabot isn't closing those PRs, but it's unclear if there's anything special about the PR above.

Observed behavior
The PR author force-pushed a branch & Oppiabot did not close the PR.

Expected behavior
I'm expecting that Oppiabot leaves a message & closes any PRs with force pushes. Is that not the case?

Screenshots
None -- see PR above.

Additional context
None

[seanlip]

Duplicate of #298.