Normalize the number before inserting into list of calls in

connectionservice

Number often get rewritten with brackets (or prepended with +). We take
a simple approach of removing non numbers so that rewriting can be
avoided.

Bug: b/28719753
Change-Id: If1525ea8564997e7ebe6ef63fccbc3c113b88e1c
(cherry picked from commit 7ec95a31)