[JsonResponse] Silent only JSON errors

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | maybe
| Fixed tickets | #11415
| License       | MIT
| Doc PR        | n/a
The most reliable way to know if the error has been triggered by this call to `json_encode` is to check the `$errfile` and `$errno`.