Move `ScreenRecordRule` to be a @ClassRule

This allows the screen to be recorded only once throughout the class, instead for each individual test to prevent a lot of mp4s being generated for each assertion and rotation permutations

Fixes: 421100393
Test: presubmits
Flag: EXEMPT test infra
Change-Id: I470feea28234f5a1a1e63fa7356cd70b9d50c118