Playwright: Convert sliding-sync test to playwright (#11989)

* Add method to send text message

* Add dockerUrl to HomeServerConfig

* Implement sliding sync proxy

* Convert tests

* Reload page after applying labs feature

* Remove converted files

* Remove timeout

* Remove sliding-sync

* Remove proxy import

* Remove reference to proxy

* wait for load

* Update date

* Convert enableLabsFeature to separate fixture

* Enable feature in fixture

* Skip over config and just write to local-storage

* Rename fixture

* Fix room header test

* Use type inference

* Override config instead of setting localstorage

* Set default language

* Always add labs feature

* Put this one test into a separate describe block

* Move labs lag within describe block

playwright/e2e/right-panel/notification-panel.spec.ts

@@ -22,6 +22,7 @@ const NAME = "Alice";
 test.describe("NotificationPanel", () => {
     test.use({
         displayName: NAME,
+        labsFlags: ["feature_notifications"],
     });
 
     test.beforeEach(async ({ app, user }) => {
@@ -29,7 +30,6 @@ test.describe("NotificationPanel", () => {
     });
 
     test("should render empty state", async ({ page, app }) => {
-        await app.labs.enableLabsFeature("feature_notifications");
         await app.viewRoomByName(ROOM_NAME);
 
         await page.getByRole("button", { name: "Notifications" }).click();