TEL-889: Nullity check for address in connection info

[genseric-ghiro]

Summary

• In SDP negotiation, a c= line without an address parses to a non-nil ConnectionInformation with a nil Address, so we need to check that the address is non-nil before doing ci.Address.Address; otherwise, this panics and crashes the process along with all the other calls.
• Also, try choosing the session-level address before directly going to the origin address.

Test

• Unit tests added