`CI`: fix if conditional in `ui_preview.yaml` (#33675)

* fix if conditional

* open

* open fix

.github/workflows/ui_preview.yaml

@@ -135,11 +135,13 @@ jobs:
 
           TABLE="${TABLE}</table>"
           TABLE="${TABLE}</details>"
+
           if $open; then
             TABLE="<details open>${TABLE}"
           else
             TABLE="<details>${TABLE}"
           fi
+
           echo "DIFF=$DIFF$TABLE" >> "$GITHUB_OUTPUT"
 
       - name: Saving proposed ui