fix: Ensure an empty string is used as the fallback

Author: smockle

action.yml

@@ -109,8 +109,8 @@ runs:
       uses: actions/github-script@v8
       with:
         script: |
-          const filings = ${{ steps.file.outputs.filings || '' }} || [];
-          const fixings = ${{ steps.fix.outputs.fixings || '' }} || [];
+          const filings = ${{ steps.file.outputs.filings || '""' }} || [];
+          const fixings = ${{ steps.fix.outputs.fixings || '""' }} || [];
           const fixingsByIssueUrl = fixings.reduce((acc, fixing) => {
             if (fixing.issue && fixing.issue.url) {
               acc[fixing.issue.url] = fixing;