Keyguard: fix codestyle

Change-Id: I3f1fbab0ae5434b09766cd69c39a133f4a7039d0
fb: disable navigation bar camera button if widget carousel is enabled

Beside that the animation which starts when dragging the camera icon
to the left is broken if the user has enabled carousel animation like
tablets it does not feel natural even when we use the right animation for it.

So diable the camera button in this case and allow only swiping the camera widget on carousel mode

Change-Id: I6ba5eda7cd4603b1644ae088401b57861e4937a1
Keyguard: let the user drag the challenge down if widgets are disabled

for the system clock widget this does not make much sense but due
that our system default is DashClock it makes a lot sense to
allow it to see more content of DashClock extensions

So allow it for overlay added app widgets if the binding was
sucessfull.

Change-Id: I0365573c6fa88117a47b01ced81eb36f75324342
fb: Keyguard disable challenge drag down on slimpin/simpuk screen

On simpin, simpuck and as well account change screen it does not make
any sense to give the user the abillity to drag down the challenge to show
the widget maximized (neither if widgets are enabled or disabled)
Reason: simpin/simpuck widget is not shown due of security reasons
and on account change the next expected behaviour is that the user gets a new
setup. So it does not make in this case as well sense

Just check for current securityscreen selection to block this behaviour. As
well move the enable/disable code to a proper place

Change-Id: I0b16d1e590252b537d6c71c4aa9b133ed832be45