Removed cache buster from client extensions script (#20668)

ref
https://linear.app/tryghost/issue/PA-71/remove-cache-bust-from-projs-in-admin
ref
15ed2eb245

- This cache buster was added in March to mitigate a client side error in pro.js,
to effectively force browsers to redownload the fixed version of the file.
- It's not needed anymore, as the error has been fixed for a few months
now, so we can safely remove it.

ghost/admin/app/controllers/application.js

@@ -27,10 +27,6 @@ export default class ApplicationController extends Controller {
         return this.config.clientExtensions?.script;
     }
 
-    get cacheBuster() {
-        return Date.now();
-    }
-
     get showNavMenu() {
         let {router, session, ui} = this;
 

ghost/admin/app/templates/application.hbs

@@ -40,7 +40,7 @@
     {{#if this.showScriptExtension}}
         {{{this.showScriptExtension.container}}}
         {{!-- template-lint-disable no-forbidden-elements --}}
-        <script src="{{this.showScriptExtension.src}}?v={{this.cacheBuster}}"></script>
+        <script src="{{this.showScriptExtension.src}}"></script>
     {{/if}}
 
     {{#if this.settings.accentColor}}