fix: e2e test pipeline requires submodule checkout

Author: enrico-kaack-comp

.github/workflows/e2e_test.yaml

@@ -62,8 +62,9 @@ jobs:
         with:
           #use inputs.checkout-ref to be able to call it from a pull_request_target workflow, since there it needs to be github.event.pull_request.merge_commit_sha and not the default
           ref: ${{ inputs.checkout-ref }}
+          submodules: true 
 
-      - uses: actions/setup-go@0a12ed9d6a96ab950c8f026ed9f722fe0da7ef32 # v5.0.2
+      - uses: actions/setup-go@0a12ed9d6a96ab950c8f026ed9f722fe0da7ef32 # v5.0.2
         with:
           go-version: '1.21'
       - run: go version