We move the mode settings because currently there is
only one item in the settings page. To fully test all logic,
we don't use fragament anymore in the controllerTest, and
test the interaction between the controller and the fragment
in the test of these two fragments.
Bug: 182992338
Test: atest ToggleScreenMagnificationPreferenceFragmentTest
atest MagnificationModePreferenceControllerTest
atest MagnificationSettingsFragmentTest
manually test
Change-Id: Ia6b0ea4f116f3215407637d7aeaddb8d8196d8fb
6269a92e16