gNMI-1.14.2 Test gNMI Subscribe with "ON_CHANGE" mode for backplane capacity counters

[rohit-rp]

Request for testing gNMI Subscribe with "ON_CHANGE" mode for backplane capacity counters

WBB is required to support gNMI Subscribe with ON_CHANGE mode for various counters. This test if to verify that DUT supports gNMI Subscribe with on_change mode for backplane capacity counters

Implement code for gNMI-1.14.2

[dplore]

I think we need to also OC descriptions for /components/component/integrated-circuit/backplane-facing-capacity. I see openconfig/public#990 in progress could be refined with the below:

• consumed-capacity is the sum of the admin-up front panel interface speeds connected to the integrated-circuit
• available-percent is total-operational-capacity / consumed-capacity

Orion will subscribe ON_CHANGE to available-percent and take action if available-percent < 100

gNMI-1.4 functional test should be updated to implement the above.