Fix missing declared accessibility PreferenceControllers.

This includes 3 fixes:

Adds missing settings:controller attribute for bold & high-contrast
text preferences.

Separates VibrationSettings into two fragments, one per fragment XML resource.
  Instead of using a conditional to choose the XML resource ID,
  we now use the conditional to choose which fragment to launch.
  This allows both fragment's preference controllers to be inspected
  by CodeInspectionTest#runSliceControllerInXmlInspection.
  Also updates the preference keys which must be unique per XML in order
  to appear in Settings Search.

Adds Magnification preference controllers to exempt-not-in-XML list.
  These controllers are for fragments that are not declared in an XML.
  See ToggleScreenMagnificationPreferenceFragment
        #getPreferenceScreenResId.

Bug: 289967175
Test: atest SettingsRoboTests:com.android.settings.accessibility
Test: atest CodeInspectionTest#runSliceControllerInXmlInspection;
      Observe no errors in the accessibility package.
Test: Open Settings > Accessibility > Vibration & haptics;
      observe vibration intensity page is shown (behavior unchanged).
      Hardcode config_vibration_supported_intensity_levels=1;
      observe vibration page with toggles is shown (behavior unchanged).
Change-Id: I257b5ad390371bedb1623af6289016b06d478707