Update keyguard to send userActivity events

Update keyguard to send userActivity events

Since the new PowerManager changes are in, keyguard needs to handle
keeping the screen awake.  This change does this in a few places in
addition to the existing security screens:

- when the widget page changes
- when the user interacts with any widget other than the status widget
- when the user taps on the target in the selector screen

Fixes bug 7273646

Change-Id: If4c76a38e9b886dd359ba96cd2aae03652007b66