fix(laravel): allow custom error handler for non-api operations

[soyuka]

Q	A
Branch?	4.1
Tickets	Closes #7466
License	MIT

The fix properly handles both issue #7058 (custom exception handler classes) and issue
#7466 (callbacks registered after booting) by:

• First checking if any renderable() callbacks registered on the ErrorHandler instance
  can handle the exception
• If not handled, delegating to the decorated handler (for custom exception handler
  classes)
• Falling back to parent::render() if no decorated handler exists

Also removed the unnecessary call to $this->decorated->render() after successfully
handling API Platform exceptions, which was causing custom handlers to be invoked for API
operations.