Redirect back to original secured route after login

### Current Limitation

When using @asgardeo/react-router, navigating to a secured route without being logged in redirects the user to Asgardeo/IS for authentication.

After successful authentication, the user is redirected to the application root (/) instead of the originally requested secured route. This results in a poor user experience. Ideally, the user should be redirected back to the exact secured route they intended to access.

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### Suggested Improvement

This can be implemented without changes to Asgardeo/IS by leveraging the OAuth2 state parameter. The SDK can encode the currently active path in the state parameter (only if the route is valid and marked as secured) and restore it after successful authentication

### Please select the package issue is related to

@asgardeo/react-router

### Version

1.1.0

### Reporter Checklist

- [x] I have searched the existing issues and this is not a duplicate.
- [x] I have provided all the necessary information.
- [x] I have verified the improvement is not available in the latest version of the package.

Start by tracing the secured-route authentication flow in @asgardeo/react-router and how the OAuth2 state parameter is created and handled after login. Confirm how valid secured paths are identified, then verify that a successful login restores the originally requested route instead of /.

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