Fix cleaning up all persistent preferred activity

Bug: 304582457
Fixes: 304582457

Test: manually tested with steps:
      1. add more than one persistent preferred activity
      2. clean up calling clearPersistentPreferredActivity()
      3. all persistent perferred activity should be cleared
(cherry picked from https://partner-android-review.googlesource.com/q/commit:f3bcc522dec694c5951c1b5d09fa014d2e20f235)
Change-Id: I726f82e9ecc34d9f5b315f91383d03ea536b8fee