This change prevents the feature from being inadvertently exposed to the
wider user base while it undergoes further refinement and stabilization
for a smoother user experience.
Test: atest SettingsUnitTests:com.android.settings.development.graphicsdriver.GraphicsDriverEnableAngleAsSystemDriverControllerJUnitTest
Test: locally build Husky and confirm the dev option is disabled, even
with the "debug.graphics.angle.developeroption.enable" prop set.
Flag: EXEMPT bugfix
Bug: b/384047927
Change-Id: I160840a25d38bf305871d7e146745df0d56f0227
5a3cfb9f0c