DO NOT MERGE. ActivityPicker shouldn't grant permissions.
This picker has no business granting any Uri permissions, so remove
any grant flags that malicious apps may have tried sneaking in.
Test: builds, boots
Bug: 32879772
Change-Id: I91c48c73287a271bd6c99e60e216dead22e68764
(cherry picked from commit 3f218e84)
(cherry picked from commit b5e93969)