Fix no response after Talkback users double-tap on Learn more in Accessibility pages

Root cause: The ag/16569955 to fix unknown items issue when using Switch Access by grouping of related content. The design change impacts AccessibilityFooterPreference#setLinkEnabled that call TextView#setMovementMethod to change components can be focusable to break the grouping relation.

Solution: Reset summary view to nonFocusable after applied TextView#setMovementMethod.

Bug: 221342261
Bug: 221339524
Bug: 223526982
Bug: 215792117
Bug: 215792876
Test: make RunSettingsRoboTests ROBOTEST_FILTER=AccessibilityFooterPreferenceControllerTest AccessibilityFooterPreferenceTest ToggleFeaturePreferenceFragmentTest
Change-Id: I4a051ea036ded264ee7bf615375177db796f74c7