Add MINMODE brightness modifier

Adding a new modifier that caps the brightness when MINMODE is active, using a Global Settings.

Bug: 433557124
Test: BrightnessMinModeModifierTest
Test: manual with adb commands
Flag: com.android.server.display.feature.flags.minmode_cap_brightness_enabled
Change-Id: I53359ce7959679c4911ed3d561d761c34528b482