use path prefix when loading editor.js for `ui.codemirror` (fixes #3122)

nicegui/elements/codemirror.js

@@ -147,7 +147,8 @@ export default {
     },
   },
   async mounted() {
-    this.CM = await import(`${this.resource_path}/editor.js`);
+    await this.$nextTick(); // NOTE: wait for window.path_prefix to be set
+    this.CM = await import(window.path_prefix + `${this.resource_path}/editor.js`);
     const CM = this.CM;
 
     // This is used to prevent emitting the value we just received from the server.