refactor(brightness suw): decouple auto brightness initialization logic for setup flow

The AccessibilitySettingsForSetupWizard class should not be responsible for managing the initial
logic of controllers, such as determining which controllers need to be dynamically added or updated
using setInSetupWizard APIs. This logic should be handled directly by the controllers themselves.

Bug: 311093618
Flag: EXEMPT bugfix
Test: atest AccessibilitySettingsForSetupWizardTest
            AutoBrightnessPreferenceControllerForSetupWizardTest
            AutoBrightnessPreferenceControllerTest
            BrightnessLevelPreferenceControllerForSetupWizardTest
            BrightnessLevelPreferenceControllerTest

Change-Id: I6065a10e72d002981c0f514543e6933d79c2aa1b