Remove "Enable widgets" checkbox from Face Unlock settings

It doesn't work anyway as we have a different option to control
widgets' behaviour.

Change-Id: I2f3c2b6f8f638c6c4d9d9c9b3cdb2facfef70039
Settings: Update DE translation

PS1:  Upload in troll free mode
PS2:  Removed some duplicated strings. WTF?

Change-Id: If37ce31ed2e78cf5b635c6e429321c8ec163533b