Toggle loading state based on config_lowResTaskSnapshotScale

Change high res loading state implementation to toggle on/off based on
config_lowResTaskSnapshotScale!=0 instead of ro.config.low_ram=true

Test: TaskSnapshotCacheTest
Test: TaskSnapshotControllerTest
Test: TaskSnapshotPersisterLoaderTest
Test: TaskSnapshotSurfaceTest
Bug: 148099851
Change-Id: I316e553a8a13fe38f1224c38f7aa717a0f628f57