Log the clipboard retrieval event into statsd

Including the source/destination package of the clipdata,
as well as the time between the set and get (copy & paste).

Bug: 402542624
Test: statsd_testdrive 1048
Flag: com.android.server.clipboard.clipboard_get_event_logging
Change-Id: I8c4f007e7e4aac3dd3a721d45a9a2c69b97718c0