Define own "cancel" string resource

Current the permission controller is using the cancel resource out of
the SettingsLib. This lib is build agains the internal API, hence it
cannot be used anymore.

Hence define own resource.

Bug: 110953302
Test: Built (also build without SettingsLib but this requires addional
      changes.)
Change-Id: Ib07e0b7a8c66ce80016d986ed40fc99817cccd19