Fix addresses truncation

Fix long addresses truncated: replace old belle_sip_object_marshal method by belle_sip_object_to_string in sal_address_as_string and sal_address_as_string_uri_only in order to no be limited by a fixed buffer size. This prevents a crash when the call gets a bad uri.

https://linphone.atlassian.net/browse/SDK-808?focusedCommentId=20675&sourceType=mention