Bug 21589105 Rescope SYSTEM_ALERT_WINDOW (UX and Settings app change)...

Overall, fixed the detection of the state of permission in the corresponding UX
to be more accurate. Also ensured that apps can actually launch the summary UX
through a custom intent.

AndroidManifest:
Adds the proper intent-filter so that apps can launch the Settings page using
intent.

strings:
Made changes to strings so that wordings are uniform everywhere and raised the
char limit due to requests from translators.

Change-Id: Ia03403641ad53bd1a33b84dae6db1739cfcf9d60