fix: Add check for currentInstance existance (#1083)

* fix: Add check for currentInstance existance

* Update packages/ckeditor5/src/plugin.js

Co-authored-by: Jose González <[email protected]>

---------

Co-authored-by: Jose González <[email protected]>

Author: 2 people

packages/ckeditor5/dist/browser/index.js

@@ -62,8 +62,8 @@ export default class MathType extends Plugin {
    * Inherited from Plugin class: Executed when CKEditor5 is destroyed
    */
   destroy() {
-    // eslint-disable-line class-methods-use-this
-    currentInstance.destroy();
+      // eslint-disable-line class-methods-use-this
+      currentInstance?.destroy();
   }
 
   /**