[IMP] web_editor: allow left-panel select to have custom active labels

Instead of the text of the selected option displayed as label, we may
want another text (especially if the choice has long text). This can
be defined on buttons with 'data-select-label'.

Part of https://github.com/odoo/odoo/pull/52211
Related to task-2197038

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

@@ -723,7 +723,11 @@ const SelectUserValueWidget = UserValueWidget.extend({
         }
 
         const activeWidget = this._userValueWidgets.find(widget => !widget.isPreviewed() && widget.isActive());
-        this.menuTogglerEl.textContent = activeWidget ? activeWidget.el.textContent : "/";
+        let value = "/";
+        if (activeWidget) {
+            value = activeWidget.el.dataset.selectLabel || activeWidget.el.textContent;
+        }
+        this.menuTogglerEl.textContent = value;
     },
 
     //--------------------------------------------------------------------------