ci: avoid depending on stack job for test-bootstrap jobs

This patch makes test-bootstrap related ci jobs only depend on
hadrian-ghc-in-ghci job to finish, consistent with other jobs in the
full-build stage generated by gen_ci.hs. This allows the jobs to be
spawned earlier and improve overall pipeline parallelism.

.gitlab-ci.yml

@@ -638,6 +638,8 @@ hackage-doc-tarball:
 
 source-tarball:
   stage: full-build
+  needs:
+    - hadrian-ghc-in-ghci
   tags:
     - x86_64-linux
   image: "registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb12:$DOCKER_REV"
@@ -659,6 +661,8 @@ source-tarball:
 
 generate-hadrian-bootstrap-sources:
   stage: full-build
+  needs:
+    - hadrian-ghc-in-ghci
   tags:
     - x86_64-linux
   image: "$DOCKER_IMAGE"