External display mode limit flag in settings

Use external display mode limit flag and override
for the flag in the settings to allow selection
of any resolutions with the refresh rate around 60

Change-Id: I180ba97eb9dfa14a386a7517f29504d369268563
Bug: 351831642
Flag: com.android.settings.flags.resolution_and_enable_connected_display_setting
Test: atest ResolutionPreferenceFragmentTest