[10.x] Update return type

[AmirRezaM75]

Update return type for getTokenForRequest method.

For example bearerToken may return null

framework/src/Illuminate/Http/Concerns/InteractsWithInput.php

Lines 50 to 55 in 5f8684b

	/**
	* Get the bearer token from the request headers.
	*
	* @return string|null
	*/
	public function bearerToken()

This will raise issue with phpstan when you come up with something like this:
$token = auth()->getTokenForRequest() ?? '';

[driesvints]

Thanks!