Fix Restart and Resize hints flickering

The flicker was due to a change in the size of the layout when the
hint was displayed. This was triggering a relayout which appeared as
a flicker.

Avoiding the resize of the layout using invisible instead of gone fixes
the problem.

Flag: EXEMPT Bug fixing
Fix: 322463856
Test: atest WMShellUnitTests:CompatUIWindowManagerTest
Test: atest WMShellUnitTests:UserAspectRatioSettingsLayoutTest

Change-Id: Ibe98841a3d951e9dde54b899781c741b6d71a5e3