Display: refactor Color Mode settings

1. Refactor Color Mode by moving color summary functionality to the ColorModeUtils
class.
2. Migrated `ColorModeUtils` from Java to Kotlin.
3. Changed ColorModePreferenceControllerTest according to changes

Bug: 390644464
Flag: EXEMPT refactoring
Test: atest com.android.settings.display
Test: atest -c packages/apps/Settings/tests/robotests/src/com/android/settings/display/colors/ColorModePreferenceControllerTest.kt
Test: atest -c packages/apps/Settings/tests/unit/src/com/android/settings/display/ColorModePreferenceFragmentTest.java

Change-Id: I55ac6129b93e4e35bd58f0313215b711ce954c0a