Fix vulnerability in CallRedirectionService.

Currently when the CallRedirectionService binding died, we didn't do
anything, which cause malicious app start activities even not run in the
background by implementing a CallRedirectionService and overriding the
onPlaceCall method to schedule a activity start job in an independent
process and then kill itself. In that way, the activity can still
start after the CallRedirectionService died. Fix this by unbinding the
service when the binding died.

Bug: b/289809991
Test: Using testapp provided in bug to make sure the test activity can't
be started
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:29b52e3cd027da2d8644450a4dee3a7d95dc0043)
Merged-In: I065d361b83700474a1efab2a75928427ee0a14ba
Change-Id: I065d361b83700474a1efab2a75928427ee0a14ba