Change aspect ratio summary and footer text

Add more education for device user that setting aspect ratio has not
been tested by the app developer. Move Aspect ratio under Apps >
Advanced instead of General.

Fix: 296160724
Test: atest UserAspectRatioAppsPageProviderTest
Change-Id: I2078f285d7bfb8de3a61c69f9d0ff3872d683ed4