Enforce trailing comma in JS on multiline (#30002)

To keep blame info accurate and to avoid [changes like
this](https://github.com/go-gitea/gitea/pull/29977/files#diff-c3422631a14edbe1e508c4b22f0c718db318be08a6e889427802f9b6165d88d6R359),
it's good to always have a trailing comma, so let's enforce it in JS.

This rule is completely automatically fixable with `make lint-js-fix`
and that's what I did here.

web_src/js/components/ContextPopup.vue

@@ -69,7 +69,7 @@ export default {
         }
         return {name: label.name, color: `#${label.color}`, textColor};
       });
-    }
+    },
   },
   mounted() {
     this.$refs.root.addEventListener('ce-load-context-popup', (e) => {
@@ -97,8 +97,8 @@ export default {
       } finally {
         this.loading = false;
       }
-    }
-  }
+    },
+  },
 };
 </script>
 <template>