Previous implementation assumes that we use the `call_subscription`
objects in:
- `call_offer_answer_ng()`
- `call_update_lookup_udp()`
- `call_request_lookup_tcp()`
when appealing to the `call_get_mono_dialogue()`, in order to
get the `call_subscription` objects, in order to then pass it
for usage in the `monologue_offer_answer()`, where the most important
again is to use monologue references stored inside
the given `call_subscription` objects.
Instead of using the `call_subscription`, just use `call_monologue`
objects as a base data objects for this work,
which will allow us in the coming commits to deprecate
the `call_subscriptions` based model and
get to the subscription model based on medias.
Change-Id: Ia9ee5ba66522929acbceca28854ebccd3705635a
Donat Zenichev
4bbbfba818