Blacklist: Avoid crash when dialog dismissed via back button.

A user usually presses the back button only
when he/she does not want the changes to be saved.
Hence we need to revert the changes that took place
when the dialog is dismissed with back button.

Change-Id: Ifa3ef41f02f11d1e1627071532d8f915e3b445b6
Lockscreen Notifications [2/2]

- Enable/disable lockscreen notifs
- Pocket mode
- Show always
- Hide Low Priority
- Hide Non Clearable
- Allow dismissing non clearable notifications
- Eenable/disable expanded notifications
- Force expanded view
- Wake on notification
- Notification count displayed at once
- Privacy Mode
- Offset to the top of the screen
- Blacklist apps (thanks @Der-Schubi and ChameleonOS)
- Custom notifications background color

Change-Id: I7e1ec5c6258ce723495060000d58601b0e4c88c0

Conflicts:
	res/values/pa_strings.xml
	res/xml/security_settings_biometric_weak.xml
	res/xml/security_settings_chooser.xml
	res/xml/security_settings_lockscreen.xml
	res/xml/security_settings_password.xml
	res/xml/security_settings_pattern.xml
	res/xml/security_settings_pin.xml