[custom channels]: test forward traffic shaper #1882

Job	Run time
backend build on ubuntu-latest	3m 4s
backend build on windows-latest	14m 13s
integration test	18m 20s
backend build on macOS-latest	5m 20s
check commits	49s
frontend tests on ubuntu-latest	2m 16s
frontend tests on windows-latest	12m 38s
lint	2m 4s
frontend tests on macOS-latest	2m 23s
RPC proto compilation check	3m 22s
unit tests	39s
unit-race	33s
check release notes updated	2s
	1h 5m 43s

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