feat(HCT): Notification 'open settings' action behavoir

The notification should open High Contrast Text page and disappear automatically when the user taps the "Open Settings" button within the notification.

Bug: 385794406
Flag: com.android.graphics.hwui.flags.high_contrast_text_small_text_rect
Test: atest SettingsRoboTests:com.android.settings.accessibility.HighContrastTextMigrationReceiverTest
Change-Id: Ibe3c343d39e3c98a8b98fb4252d5f5a37d1aaa49