[Multiparentchain] add support for third parentchain `Target_B` #3606

Job	Run time
fmt	1m 48s
Cancel Previous Runs	5s
clippy	1m 40s
build-test (sidechain, sidechain, integritee-builder-sgx, HW, dcap)	2m 2s
build-test (offchain-worker, offchain-worker, integritee-builder-sgx, HW, dcap)	2m 2s
build-test (teeracle, teeracle, integritee-builder-sgx, HW, dcap)	2m 2s
build-test (sidechain-evm, sidechain, evm,dcap, integritee-builder-sgx, HW)	2m 2s
integration-tests (M6, sidechain, demo-indirect-invocation, test-runner-sgx, HW)	13s
integration-tests (M8, sidechain, demo-direct-call, test-runner-sgx, HW)	12s
integration-tests (Sidechain, sidechain, demo-sidechain, test-runner-sgx, HW)	12s
integration-tests (M6, offchain-worker, demo-indirect-invocation, test-runner-sgx, HW)	11s
integration-tests (Teeracle, teeracle, demo-teeracle, test-runner-sgx, HW)	11s
integration-tests (Teeracle, teeracle, demo-teeracle-generic, test-runner-sgx, HW)	12s
integration-tests (Benchmark, sidechain, sidechain-benchmark, test-runner-sgx, HW)	12s
integration-tests (EVM, sidechain-evm, demo-smart-contract, test-runner-sgx, HW)	11s
Release Build of teeracle	1s
Draft Release	1s
	13m 17s

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