Validate error_reporting to hide silented errors

After pushing #118 on production, I realized that silented errors are reported to Sentry. This is because the '@' modifier internally modify the value of `error_reporting`.

I've added `error_reporting()` check in `handleError()` (reverting to the behavior of #104 of @m8rge).

With this code, errors will be sent to Sentry only if:
1. The error code matches `error_reporting()`
2. And the error code matches `$error_types` set in `registerErrorHandler()`. (-1 = 1111111111... is all by default).