Disable nav bar assertion until bug is fixed.

Depending on the scenario, the navbar becomes invisible and reappears
in the trace. This makes the test flaky.

Bug: 167747321
Test: atest FlickerTests
Change-Id: I7fbf4a5ab7f96abd1938dad0bb626fd909dd65fc

tests/FlickerTests/src/com/android/server/wm/flicker/CommonAssertions.kt

@@ -109,7 +109,7 @@ fun LayersAssertion.navBarLayerRotatesAndScales(
     }
 
     if (startingPos == endingPos) {
-        all("navBarLayerRotatesAndScales", enabled, bugId = 167747321) {
+        all("navBarLayerRotatesAndScales", enabled = false, bugId = 167747321) {
             this.hasVisibleRegion(FlickerTestBase.NAVIGATION_BAR_WINDOW_TITLE, startingPos)
         }
     }