Invoke service connection consumer outside the object lock

The consumer may contain arbitrary operations which may
acquire the local lock again and lead to dead lock.

Currently forEachConnection is only called from
disconnectActivityFromServices which is very rare to be called
(activity destroyed without unbind service). So a local copy
should be fine.

Bug: 275277537
Test: atest ActivityRecordTests#testActivityServiceConnectionsHolder
Change-Id: If26a0cb9970cf5318cd0477adcc0fe07e98aaed9