Always report mandatory insets for button nav

Fixes: 340134342
Fixes: 343817842
Test: atest android.systemui.cts.WindowInsetsBehaviorTests
Test: Verify mandatory insets vs window bounds in various
      orientations when folded/unfolded
Change-Id: I18d4f5d212d16c62d15d84b4842b3d20c0d8c5ae
diff --git a/quickstep/src/com/android/launcher3/taskbar/TaskbarInsetsController.kt b/quickstep/src/com/android/launcher3/taskbar/TaskbarInsetsController.kt
index e1ddb6a..0b60e45 100644
--- a/quickstep/src/com/android/launcher3/taskbar/TaskbarInsetsController.kt
+++ b/quickstep/src/com/android/launcher3/taskbar/TaskbarInsetsController.kt
@@ -236,7 +236,8 @@
             provider.insetsSize = getInsetsForGravityWithCutout(contentHeight, gravity, endRotation)
         } else if (provider.type == mandatorySystemGestures()) {
             if (context.isThreeButtonNav) {
-                provider.insetsSize = Insets.of(0, 0, 0, 0)
+                provider.insetsSize = getInsetsForGravityWithCutout(contentHeight, gravity,
+                    endRotation)
             } else {
                 val gestureHeight =
                         ResourceUtils.getNavbarSize(