Add logging for direct share target

To answer the question if users share mainly with 1 or 2 direct targets
or with a multitude of contacts, we need to log the direct target +
package name. For privacy, this gets hashed with a salt that expires by
default every 7 days. The PH flag will allow us to change the expiration
time if we obtain PWG permission for that.

Bug: 126365511
Test: New test in ChooserActivityTest + manual testing of consistency
and flag rollout using adb shell device_config put systemui
hash_salt_max_days with multiple values

Change-Id: Ib4255b3eb39ca91ccb5803dc036ffe0ea83a27c9