Fix resource server autoconfig to not require OAuth2 client

In this commit, we remove the InMemoryClientRegistrationRepository class
from the OAuth2ResourceServerAutoConfiguration clause, after which we
become independent of the OAuth2 client side.

Closes: gh-329

Signed-off-by: Andrey Litvitski <andrey1010102008@gmail.com>

Author: therepanic

spring-grpc-server-spring-boot-autoconfigure/src/main/java/org/springframework/boot/grpc/server/autoconfigure/security/OAuth2ResourceServerAutoConfiguration.java

@@ -52,7 +52,6 @@
 import org.springframework.grpc.server.security.GrpcSecurity;
 import org.springframework.security.config.Customizer;
 import org.springframework.security.config.ObjectPostProcessor;
-import org.springframework.security.oauth2.client.registration.InMemoryClientRegistrationRepository;
 import org.springframework.security.oauth2.core.DelegatingOAuth2TokenValidator;
 import org.springframework.security.oauth2.core.OAuth2TokenValidator;
 import org.springframework.security.oauth2.jose.jws.SignatureAlgorithm;
@@ -77,6 +76,7 @@
  * {@link EnableAutoConfiguration Auto-configuration} for gRPC OAuth2 resource server.
  *
  * @author Dave Syer
+ * @author Andrey Litvitski
  * @since 1.0.0
  */
 // All copied from Spring Boot
@@ -88,8 +88,7 @@
 		after = { GrpcSecurityAutoConfiguration.class, GrpcServerFactoryAutoConfiguration.class })
 @EnableConfigurationProperties(OAuth2ResourceServerProperties.class)
 @ConditionalOnSpringGrpc
-@ConditionalOnClass({ InMemoryClientRegistrationRepository.class, BearerTokenAuthenticationToken.class,
-		ObjectPostProcessor.class })
+@ConditionalOnClass({ BearerTokenAuthenticationToken.class, ObjectPostProcessor.class })
 @ConditionalOnMissingBean(GrpcServletConfiguration.class)
 @ConditionalOnBean({ BindableService.class, GrpcSecurityAutoConfiguration.class })
 @Import({ Oauth2ResourceServerConfiguration.JwtConfiguration.class,