fix(test-runner): fix default export breaking on installation tests (#7331)

Author: JoelEinbinder

packages/playwright-test/index.mjs

@@ -25,4 +25,4 @@ export const errors = playwright.errors;
 export const _electron = playwright._electron;
 export const _android = playwright._android;
 export const test = playwright.test;
-export default playwright.default;
+export default playwright.test;