Change encryption preference's summary accordingly

Change encryption preference's summary accordingly

With this change a summary to the encryption preference was added.

https://android.googlesource.com/platform/packages/apps/Settings/+/415ce9a77d44732966fbab641d1ecaa8e8688381

The problem is that even if you're not encrypted, it says that your phone is.
Is very misleading to the user that don't bother to enter the actual preference
and want to see if they are. This fixes that.

This is cherry-picked from
https://android-review.googlesource.com/#/c/platform/packages/apps/Settings/+/517875/

Test: Go into Settings/Security & Location
Fixes: 68691666
Fixes: 68542516
Change-Id: Iaeaffd340f2e248748f244a947aa71eb8ad4ab94