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/standalone/swagger.js

@@ -21,11 +21,11 @@ window.addEventListener('load', async () => {
     docExpansion: 'none',
     defaultModelRendering: 'model', // don't show examples by default, because they may be incomplete
     presets: [
-      SwaggerUI.presets.apis
+      SwaggerUI.presets.apis,
     ],
     plugins: [
-      SwaggerUI.plugins.DownloadUrl
-    ]
+      SwaggerUI.plugins.DownloadUrl,
+    ],
   });
 
   window.ui = ui;