Provide a way to ToggleA11yServicePreferenceFragment via Intent

Intent can only open the list of a11y services in Settings currently.
PermissionController needs a way to open the screen with the a11y
service toggle.

Bug: 123693167
Test: manual
Test: atest AccessibilityDetailsSettingsFragmentTest
Change-Id: I32ed39330cf9e4c18a1747521fb65eb911d1c6e4