dataconnect.yml: fix [[ -v $issue_from_pr_body ]] to [[ -v issue_from_pr_body ]] (remove the $)

Author: dconeybe

.github/workflows/dataconnect.yml

@@ -289,7 +289,7 @@ jobs:
             issue_from_pr_body=$(gh issue view "$pr_number" --json body --jq '.body' -R ${{ github.repository }} | sed -En 's#(\s|^)trksmnkncd_notification_issue=([0-9]+)(\s|$)#\2#p')
           fi
 
-          if [[ -v $issue_from_pr_body ]] && [[ -n $issue_from_pr_body ]] ; then
+          if [[ -v issue_from_pr_body ]] && [[ -n $issue_from_pr_body ]] ; then
             issue="$issue_from_pr_body"
           elif [[ '${{ github.event_name }}' == 'schedule' ]] ; then
             # See https://github.com/firebase/firebase-android-sdk/issues/6857