[FIX] web_editor: fix editor-lock after gallery image reordering again

The bug was already solved with [1] but was reintroduced later for
another reason. [1] solved the problem by checking that the current
option is not destroyed before asking for an UI update thanks to a
trigger_up (the option was destroyed because of image reordering). The
bug is now reintroduced for the same basic reason: a new trigger_up was
added between the potential option destroy and the destroy check, so
if the option is destroyed, that trigger_up fails to be triggered and
the editor is locked.

This commit solves the problem once and for all, hopefully, with a
more robust solution: only destroy options when none is being
processed. That way we ensure that all trigger_up occuring during an
option activation / update can be properly done.

[1]: https://github.com/odoo/odoo/commit/9eeea4c4107dc15984c475582d5ee58a17cd2568

X-original-commit: 7770430f78ee9e122a732fa042226d362467158e

addons/web_editor/static/src/js/editor/snippets.editor.js

@@ -1094,12 +1094,15 @@ var SnippetsMenu = Widget.extend({
      * Updates the cover dimensions of the current snippet editor.
      */
     updateCurrentSnippetEditorOverlay: function () {
-        this.snippetEditors = _.filter(this.snippetEditors, function (snippetEditor) {
+        this.snippetEditors = this.snippetEditors.filter(snippetEditor => {
             if (snippetEditor.$target.closest('body').length) {
                 snippetEditor.cover();
                 return true;
             }
-            snippetEditor.destroy();
+            // Destroy options whose $target are not in the DOM anymore but
+            // only do it once all options executions are done.
+            this._mutex.exec(() => snippetEditor.destroy());
+            return false;
         });
     },
 

addons/web_editor/static/src/js/editor/snippets.options.js

@@ -2493,13 +2493,6 @@ const SnippetOptionWidget = Widget.extend({
             // Call widget option methods and update $target
             await this._select(previewMode, widget);
 
-            // Enabling an option and notifying that the $target has changed
-            // may destroy the option (if the DOM is altered in such a way the
-            // option is not attached to it anymore). In that case, we must not
-            // wait for a response to the option update.
-            if (this.isDestroyed()) {
-                return;
-            }
             await new Promise(resolve => setTimeout(() => {
                 // Will update the UI of the correct widgets for all options
                 // related to the same $target/editor if necessary