Remove backing fields for ColorAndMotionScreen

Bug: 373451690
Flag: EXEMPT refactor
Test: atest
Change-Id: I371bd221b6079c9816725e5253e110eef423fc5e

tests/robotests/src/com/android/settings/accessibility/ColorAndMotionScreenTest.kt

@@ -27,7 +27,9 @@ import org.junit.runner.RunWith
 @RunWith(AndroidJUnit4::class)
 class ColorAndMotionScreenTest : CatalystScreenTestCase() {
     override val preferenceScreenCreator: PreferenceScreenCreator = ColorAndMotionScreen()
-    override val flagName: String = Flags.FLAG_CATALYST_ACCESSIBILITY_COLOR_AND_MOTION
+
+    override val flagName: String
+        get() = Flags.FLAG_CATALYST_ACCESSIBILITY_COLOR_AND_MOTION
 
     override fun migration() {}
 
@@ -35,4 +37,4 @@ class ColorAndMotionScreenTest : CatalystScreenTestCase() {
     fun key() {
         assertThat(preferenceScreenCreator.key).isEqualTo(ColorAndMotionScreen.KEY)
     }
-}
+}