[RESTRICT AUTOMERGE] Pass correct realCallingUid to startActivity() if...

[RESTRICT AUTOMERGE] Pass correct realCallingUid to startActivity() if provided by PendingIntentRecord#sendInner()

Previously we'd ignore realCallingPid and realCallingUid that
PendingIntentRecord#sendInner() provided to startActivityInPackage().
Now we correctly pass it on, preserving past behaviour if none
provided.

Test: manual; we added logging statements to check the value of realCallingUid
in startActivitiesMayWait when launching the calendar app from the calendar widget
and verified that it was the calendar uid rather than the system uid.

Bug: 123013720
Change-Id: If0c0b67880c2e7a8774f31fbb1ba5f50544d2972
(cherry picked from commit b255e64a)