[OptionsResolver] fix count() and exceptions

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Please see commits.
Well BadMethodCallException talks about `callbacks` which is not true in the validator component. So it does not fit there either according to the definition. But I'm ok to change it back.