Keep mCanAffectSystemUiFlags to be false while in PiP

Introduced in ag/14105379 and it appears that a Window should not be
able to affect system ui flags when it's in PiP mode. Reset this flag
when we're leaving PiP mode.

Video: http://recall/-/aaaaaabFQoRHlzixHdtY/dH4cGuTxpEYpm2myTNraJI
Bug: 234082669
Test: follow the reproduce steps in bug, see also the video \
      1. status bar does not flash when launch another app \
      2. status bar always visible when launch Settings \
      3. status bar turns back invisible when exiting to fullscreen
Change-Id: I4d64c19750e69a33ad9ec5962ee4e62320b921af

services/core/java/com/android/server/wm/Task.java

@@ -4427,13 +4427,13 @@ class Task extends TaskFragment {
                     : WINDOWING_MODE_FULLSCREEN;
         }
         if (currentMode == WINDOWING_MODE_PINNED) {
+            // In the case that we've disabled affecting the SysUI flags as a part of seamlessly
+            // transferring the transform on the leash to the task, reset this state once we're
+            // moving out of pip
+            setCanAffectSystemUiFlags(true);
             mRootWindowContainer.notifyActivityPipModeChanged(this, null);
         }
         if (likelyResolvedMode == WINDOWING_MODE_PINNED) {
-            // In the case that we've disabled affecting the SysUI flags as a part of seamlessly
-            // transferring the transform on the leash to the task, reset this state once we've
-            // actually entered pip
-            setCanAffectSystemUiFlags(true);
             if (taskDisplayArea.getRootPinnedTask() != null) {
                 // Can only have 1 pip at a time, so replace an existing pip
                 taskDisplayArea.getRootPinnedTask().dismissPip();