[8.x] Improve content negotiation for exception handling

[bilfeldt]

This is an update to the rejected PR #39361 which was incorrectly (my bad 🤦 ) only targeting AuthenticationException (pointed out by Taylor here).

This PR is almost identical but with two important changes:

1. Uses shouldReturnJson() for all exceptions (done so in the main function render() but also in the protected functions called by this method).
2. Added the exception as parameter to the shouldReturnJson method so that more complex logic can be performed by overriding this simple method. Requested by Taylor Otwell here

The new possibilities added by this PR is as already explained in PR #39361:

Well imagine an API request with header Accept: text/csv; application/json. For succesfull responses we return a csv response but in case of an exception then we return a json response. Currently this is not possible without overriding the render() method because $request->wantsJson() returns false (arguable not ideal but intentionally left out from this PR).

I would consider this PR as a non-breaking change since it merely extracts logic into a new method, but will let Dries and Graham discuss semantics about the proper definition of "non-breaking change" 😄

p.s. I was not able to edit PR #39361 hence this new PR - I apologize if it is in fact possible to edit a rejected PR (please share info about how this is done if anyone holds this info 👍 )