[8.x] Get statusText from Response protected property

[taylormaguire]

Description:
Currently you are able to get the statusCode and content from a response. Content returns back the entire HTML output in some cases. When you need to render a Custom Error Page in the Exceptions\Handler for generic status codes like 403, 404, etc. it is beneficial in some cases to return the statusText protected property.

Use Case:
Rendering a custom error page for production when using Inertia.js to avoid using the error modal behaviour meant for local development and not production, as per Inertia documentation. Passing through the statusText in addition to the statusCode allows for both pre-defined error text to pass through to the custom error page/component.

This should not break any existing features and only extends out statusText in the same way that statusCode is passed down.