fix: when PR raised from fork, skip the attach-sovereign-rollup workflow #2731

Job	Run time
run-without-args	9m 50s
list-ymls	3s
additional-services	11m 24s
pre-deployed-gas-token	11m 26s
attach-additional-cdks	16m 29s
deploy-to-external_l1	10m 8s
attach-sovereign-rollup	16m 13s
run-with-args (./.github/tests/combinations/fork11-legacy-zkevm-stack-rollup.yml)	7m 40s
run-with-args (./.github/tests/combinations/fork11-new-cdk-stack-cdk-validium.yml)	9m 49s
run-with-args (./.github/tests/combinations/fork11-new-cdk-stack-rollup.yml)	9m 36s
run-with-args (./.github/tests/combinations/fork12-new-cdk-stack-cdk-validium.yml)	10m 12s
run-with-args (./.github/tests/combinations/fork12-new-cdk-stack-rollup.yml)	9m 22s
run-with-args (./.github/tests/combinations/fork13-new-cdk-stack-cdk-validium.yml)	10m 54s
run-with-args (./.github/tests/combinations/fork13-new-cdk-stack-rollup.yml)	9m 42s
run-with-args (./.github/tests/combinations/fork9-legacy-zkevm-stack-cdk-validium.yml)	7m 33s
run-with-args (./.github/tests/combinations/fork9-legacy-zkevm-stack-rollup.yml)	7m 41s
run-with-args (./.github/tests/combinations/fork9-new-cdk-stack-cdk-validium.yml)	9m 33s
run-with-args (./.github/tests/combinations/fork9-new-cdk-stack-rollup.yml)	9m 52s
run-with-args (./.github/tests/gas-token/auto.yml)	10m 9s
run-with-args (./.github/tests/op-rollup/custom.yml)	23m 47s
run-with-args (./.github/tests/op-rollup/default.yml)	23m 40s
run-with-args (./.github/tests/static-ports/custom-static-ports.yml)	10m 4s
run-with-args (./.github/tests/static-ports/default-static-ports.yml)	9m 58s
	4h 15m 5s

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