Fix "Enable ANGLE" switch behavior when Developer Option Switch is off

Fix below bugs:
1) When developer option switch is turned off,
"Enable ANGLE" switch is not disabled. Fixed it in
GraphicsDriverEnableAngleAsSystemDriverController::update().

2) When user turns off developer option switch,
a restart is not always mandatory. However, we should ask
user to restart the device is "Enable ANGLE" is forced to
change due to developer option switch turning off.
Fixed it in DevelopmentSettingsDashboardFragment::onSwitchChanged().

3) When user turns off developer option switch and
the reboot dialog pops up, user can dismiss the dialog by
not clicking either POSITIVE_BUTTON or NEGATIVE_BUTTON.
We should enforce user to click the button and disallow the
option to dimiss the dialog by touching screen areas
outside the window's bounds.
Fixed it in DisableDevSettingsDialogFragment.java.

Did a few clean-up and in
GraphicsDriverEnableAngleAsSystemDriverController.java, and updated
unit test to reflect new code behavior.

Bug: b/270994705
Test: m; flash and device can boot.
Test: atest -c GraphicsDriverEnableAngleAsSystemDriverControllerJUnitTest
Test: atest GraphicsDriverEnableAngleAsSystemDriverControllerTest
Test: atest SettingsRoboTests:FreeformWindowsPreferenceControllerTest
Test: atest SettingsRoboTests:DesktopModePreferenceControllerTest

Change-Id: I199b2fe59b6ad948b753793254c822a293d8b40d