[FIX] web: AbstractStorageService should destroy its storage

If that storage is destroy-able (aka RamStorage), storage objects are
created "inline" without attachment (as they may or may not be parented)
and this means those created implicitly in tests can't be tracked and
cleanly destroyed even by destroying the storage service object.

closes odoo/odoo#30790

addons/web/static/src/js/core/abstract_storage_service.js

@@ -13,6 +13,17 @@ var AbstractStorageService = AbstractService.extend({
     // this abstraction
     storage: null,
 
+    /**
+     * @override
+     */
+    destroy: function () {
+        // storage can be permanent or transient, destroy transient ones
+        if ((this.storage || {}).destroy) {
+            this.storage.destroy();
+        }
+        this._super.apply(this, arguments);
+    },
+
     //--------------------------------------------------------------------------
     // Public
     //--------------------------------------------------------------------------