Disable ONU device: TPs are deleted incompletely in TT multi-UNI scenario

The following TT-scenario is used for the ONU under test:
hsia, TP=64, single-instance TCONT per ONU (one TCONT per ONU)
voip, TP=65, single-instance TCONT per ONU
mcast, TP=66, multi-instance TCONT per ONU (one TCONT per UNI)

After the command "voltctl device disable" was applied on the ONU, all flows are deleted, but only mcast TP 66 is deleted too. Both TPs with single-instance TCONT configuration are still present in etcd data of the ONU adapter (see attachments). This is caused by missing DeleteTCont requests from OLT adapter for the TCONTs (allocation ids) which corresponds to the single-instance TPs 64 and 65 (according to my understanding one request for each UNI id using this TCONT/TP is necessary).

Note: Among other issues this behaviour is one of the reasons why https://jenkins.opencord.org/view/VOLTHA-2.X-Tests/job/periodic-voltha-unitag-subscriber-tt-test-bbsim/ is runnig instable.