MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/79142
Issue: https://gitlab.com/gitlab-org/gitlab/-/issues/350397

We are looping over the 'active' discussions, active is when
the discussion is on an 'active' diff (not outdated), regardless of it is resolved or
not. We then were calling the ResolvedNotificationService, which only
checks if the discussions are resolved. But these two are mututaly
exclusive, one can be active _and_ resolved.

So in the case that we have only one active resolved discussion which
doesn't get outdated, the ResolvedNotificationService will be called
each time this method is called, and this service will handle it as if
we have just resolved all the discussions, when in fact we may not have
resolved any discussions when calling the UpdateDiffPositionService.

So we now keep track of if all the active discussions are resolved before
calling the UpdateDiffPositionService, and then compare this to after
the update service is called, and depending on this, we may or may not
call the ResolvedNotification service.

If we go from:
Before Update Service call | After Update service call | Call Resolved
False | True | True
False | False | False
True | True | False

We only want to call the ResolvedNotificationService if we have go from
having unresolved active, to all the active being resolved, otherwise there is no need
to call it as the check in ResolvedNotification will be false. And when
all the active discussions are already resolved, the notification
service will already have been called, so no need to call it again.

Changelog: fixed