manager: fix active_connection_find()
Commit 33b9fa3a ("manager: Keep volatile/external connections while referenced by async_op_lst") changed active_connection_find() to also return active connections that are not yet activating but are waiting authorization.
This has side effect for other callers of the function. In particular, _get_activatable_connections_filter() should exclude only ACs that are really active, not those waiting for authorization.
Otherwise, in ensure_master_active_connection() all the ACs waiting authorization are missed and we might fail to find the right master AC.
Add an argument to active_connection_find to select whether include ACs waiting authorization.
Fixes: 33b9fa3a ('manager: Keep volatile/external connections while referenced by async_op_lst')