PIE: EdgeGestureService: Add flags LONG_LIVING | UNRESTRICTED

Following PhoneWindowManager enforcing.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
SystemUI: Iterate only over existing Pie snap points
PIE: Improve assistant handling

Run it from SearchPanelView and determinate before, at PieMenu creation,
if we have any assistant available or not.

Some cleanup too.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
Change-Id: I986a5e5257f432acd58dd2d75fc13f2b772c7453

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java
PIE: Fix assistant issues

We should check if we have a search assistant any time pie is drawed, not
just on init. Also restore previous intent null check way instead of calling
SearchPanelView (may not be initialized yet at boot when pie and immersive are on).
Fix also an old bug, once activated for first time, on first google now swipe up
nothing happened (the check done at first init returned false).

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>