Use FooterPreference in xml explicitly

Removed the FooterPreferenceMixin from the ChooseAccountFragment page.

Fixes: 139043643
Test: manual test
Test: make RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.accounts
Change-Id: I2b6ebef7f8ca0684afd75ec9bdd742a78a771bcd
4 files changed