[Multiparentchain] add support for third parentchain `Target_B` #3613

Job	Run time
Cancel Previous Runs	5s
clippy	35m 2s
build-test (sidechain, sidechain, integritee-builder-sgx, HW, dcap)	25m 19s
build-test (offchain-worker, offchain-worker, integritee-builder-sgx, HW, dcap)	25m 1s
build-test (teeracle, teeracle, integritee-builder-sgx, HW, dcap)	24m 12s
build-test (sidechain-evm, sidechain, evm,dcap, integritee-builder-sgx, HW)	25m 27s
fmt	6m 43s
integration-tests (M6, sidechain, demo-indirect-invocation, test-runner-sgx, HW)	11m 32s
integration-tests (M8, sidechain, demo-direct-call, test-runner-sgx, HW)	7m 32s
integration-tests (Sidechain, sidechain, demo-sidechain, test-runner-sgx, HW)	7m 24s
integration-tests (M6, offchain-worker, demo-indirect-invocation, test-runner-sgx, HW)	12m 7s
integration-tests (Teeracle, teeracle, demo-teeracle, test-runner-sgx, HW)	5m 35s
integration-tests (Teeracle, teeracle, demo-teeracle-generic, test-runner-sgx, HW)	4m 52s
integration-tests (Benchmark, sidechain, sidechain-benchmark, test-runner-sgx, HW)	6h 0m 54s
integration-tests (EVM, sidechain-evm, demo-smart-contract, test-runner-sgx, HW)	7m 32s
Release Build of teeracle	0s
Draft Release	0s
	9h 19m 17s

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