Use group redirections for multiple outputs, prevent glob expansion of PR_NUMBER

Co-authored-by: Seth Flynn <getchoo@tuta.io>
Signed-off-by: Rachel Powers <508861+Ryex@users.noreply.github.com>

.github/workflows/merge-blocking-pr.yml

@@ -39,8 +39,10 @@ jobs:
                 )) as $i ([]; . + [$i])
               '
           )
-          echo "deps=$blocked_prs" >> "$GITHUB_OUTPUT"
-          echo "numdeps=$(jq -r '. | length' <<< "$blocked_prs")" >> "$GITHUB_OUTPUT"
+          {
+            echo "deps=$blocked_prs"
+            echo "numdeps=$(jq -r '. | length' <<< "$blocked_prs")" 
+          }  >> "$GITHUB_OUTPUT"
 
       - name: Trigger Blocked PR Workflows for Dependants
         if: fromJSON(steps.gather_deps.outputs.numdeps) > 0