[flexiglass] Rename "throttling" to "lockout".

Bonus: Make the bouncer dialog code more generic, not lockout-specific.
This helps prepare for the upcoming wipe dialog (see b/306559035).

Fix: 315118723
Bug: 306559035
Bug: 314757822
Test: Unit tests still pass.
Flag: ACONFIG com.android.systemui.scene_container DEVELOPMENT
Change-Id: I978fb681476ab5fba801215c951a6dfbcb7787a3
18 files changed