fix(adapter-nextjs): make createAuthRouteHandlers interface work in both App and Pages routers

[HuiSF]

Description of changes

Issue #, if available

Make the public handler function type as any to let the single function to be compatible with the type checks that happens in both the App router and Pages router.

• Runtime validation on the handler parameters are enforced.

Description of how you validated changes

• npx next build

Checklist

• [x] PR description included
• [x] yarn test passes
• [ ] Unit Tests are changed or added
• [ ] Relevant documentation is changed or added (and PR referenced)

Checklist for repo maintainers

• [ ] Verify E2E tests for existing workflows are working as expected or add E2E tests for newly added workflows
• [ ] New source file paths included in this PR have been added to CODEOWNERS, if appropriate

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.