Fix crash on e2e test failure (#16556)

If an e2e test fails on a website, the driver will crash on this line
because it can't find a reference to `stateHooks`. That variable is
only set in our UI, not on other sites.

test/e2e/webdriver/driver.js

@@ -416,7 +416,7 @@ class Driver {
     await fs.writeFile(`${filepathBase}-dom.html`, htmlSource);
     const uiState = await this.driver.executeScript(
       () =>
-        window.stateHooks.getCleanAppState &&
+        window.stateHooks?.getCleanAppState &&
         window.stateHooks.getCleanAppState(),
     );
     await fs.writeFile(