[springdoc-openapi-data-rest] @RestResource(exported = false) does not work for custom existsByXyz methods

[uqix]

Describe the bug

@RestResource(exported = false) does not work for custom existsByXyz methods

To Reproduce
Steps to reproduce the behavior:

• What version of spring-boot you are using? 2.5.4
• What modules and versions of springdoc-openapi are you using? springdoc-openapi-data-rest
• Provide with a sample code (HelloController) or Test that reproduces the problem

package app.pricequery;

import org.springframework.data.repository.CrudRepository;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;
import org.springframework.data.rest.core.annotation.RestResource;

@RepositoryRestResource
public interface DisabledPriceQueryRepository extends CrudRepository<DisabledPriceQuery, Long> {

    // case 1 error: org.springframework.data.mapping.MappingException: Couldn't find PersistentEntity for type boolean!
    @RestResource(exported = false)
    boolean existsByUserNicknameAndMatchKeyword(String userNickname, String matchKeyword);

    // case 2 works
    @RestResource(exported = false)
    DisabledPriceQuery findByUserNickname(String userNickname);

    // case 3 works
    @RestResource(exported = false)
    @Override
    void deleteById(Long id);
}

Expected behavior

• existsByUserNicknameAndMatchKeyword method should not be exposed.

[bnasslahsen]

@uqix,

Not reproducible using v1.6.8. See the updated test case.
If you believe you are facing an issue, make sure you provide a Minimal, Reproducible Example - with HelloController that reproduces the problem.