[FIX] website: restore creating special pages via "add page" dialog

Commit at [1] factorized some code and in the process used a service
that was not declared. This prevented to use the "add page" dialog
(which allows to create pages via the "+ New" button) to create special
pages ".js", ".css". That feature will likely be removed or reworked
in a future update though.

[1]: https://github.com/odoo/odoo/commit/58698f848703395ff680bc7586ecc8eec4fb61ae

X-original-commit: 21b90ff8bdad22b6beea1b6b5a6d70276817c00e
Part-of: odoo/odoo#102991

addons/website/static/src/components/dialog/dialog.js

@@ -85,6 +85,7 @@ export class AddPageDialog extends Component {
         this.website = useService('website');
         this.orm = useService('orm');
         this.http = useService('http');
+        this.action = useService('action');
 
         this.state = useState({
             addMenu: true,