Rename ViewRefactorFlag to RefactorFlag; make FeatureFlags exemption clearer.

* I'm removing the word View from the class so that this can be used in other contexts.
* I'm adding an requirement that you call `forView` if you want to omit the FeatureFlags.

Bug: 290365128
Test: atest SystemUITests
Change-Id: I96a273a660f05fc398ee7eb68e19b76aa8db0bc5