fix(test/e2e): Increase timeout of flaky basepath test (#79481)
Reducing this timeout from the default of 3000ms to 2500ms makes the failure reproduce 100% of the time for me. Increasing it, I'm unable to reproduce the issue.
Tested with:
```
pnpm test-dev-turbo test/e2e/basepath/router-events.test.ts 'should use urls with basepath in router events for failed route change'
```
This appears fail sometimes with turbopack, but never with webpack. For some reason, webpack is faster at building these error pages? There's a few redirects that have to happen here, and if you get unlucky, those redirects might not finish within 3 seconds on a cold turbopack session.
