Request keyguard dismissal from suspend dialog

Sometimes a suspended app may be started while the device is locked. The
suspend dialog should request the user to unlock in these cases.

Test: Manual:
1. Suspend camera app.
2. Lock the screen.
3. Try to launch the camera while the screen is locked, e.g., by double
tapping the power button.

Bug: 157867645
Change-Id: Ie3b5e2903804bc8b385de4fc9276dd55a8108c0f
Merged-In: Ie3b5e2903804bc8b385de4fc9276dd55a8108c0f