Add error to action (#3335)

Author: cprecioso

.github/actions/fetch-nightly-cli/action.yaml

@@ -32,6 +32,14 @@ runs:
             --json databaseId \
             --jq '.[0].databaseId'
         )
+
+        if [ -z "$run_id" ]; then
+          # Using the ::error:: prefix lets GitHub handle it as a special string, and shows up as a red error in the logs.
+          # https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-commands#setting-an-error-message
+          echo "::error::No successful workflow runs found for branch '$BRANCH'."
+          exit 1
+        fi
+
         echo "run_id=$run_id" >> $GITHUB_OUTPUT
       env:
         GH_REPO: wasp-lang/wasp