Wait for all notifications protocols to be open before reporting opening (#6821)

* Wait for all notifications protocols to be open before reporting opening

* Update client/network/src/protocol/generic_proto/handler/notif_out.rs

Co-authored-by: Max Inden <mail@max-inden.de>

* Concern

* Fix attempt

* Another fix attempt

* Update client/network/src/protocol/generic_proto/handler/group.rs

Co-authored-by: Max Inden <mail@max-inden.de>

Co-authored-by: parity-processbot <>
Co-authored-by: Max Inden <mail@max-inden.de>