test(Playwright): add before mount theme and mobile provider (#857)

playwright/playwright/index.tsx

@@ -1,2 +1,15 @@
-// Import styles, initialize component theme here.
+import {MobileProvider, ThemeProvider} from '@gravity-ui/uikit';
+import {beforeMount} from '@playwright/experimental-ct-react/hooks';
+import React from 'react';
+
 import './index.scss';
+
+beforeMount(async ({App}) => {
+    return (
+        <ThemeProvider theme="light">
+            <MobileProvider>
+                <App />
+            </MobileProvider>
+        </ThemeProvider>
+    );
+});