Add detailed error handling in non-production environments for verifyUserCanAccessChannel method

[doganarif]

Summary:
This PR modifies the verifyUserCanAccessChannel method to provide more informative error messages when the application is not in production, helping with debugging during development. In production environments, the method continues to return generic error responses for security reasons.

Changes:

• Introduced an environment check using App::environment('production') to differentiate between production and non-production environments.
• In non-production environments, detailed error messages are thrown, explaining why the access was denied.
• In production environments, the generic AccessDeniedHttpException is maintained for security.

Why:
This change improves the debugging experience by providing more context in non-production environments, while maintaining secure error handling in production.

[taylorotwell]

Thanks for your pull request to Laravel!

Unfortunately, I'm going to delay merging this code for now. To preserve our ability to adequately maintain the framework, we need to be very careful regarding the amount of code we include.

If applicable, please consider releasing your code as a package so that the community can still take advantage of your contributions!