OZG-4095 Avoid restClient bean

src/main/java/de/ozgcloud/nachrichten/postfach/osiv2/config/ApiClientConfiguration.java

@@ -44,14 +44,13 @@ public class ApiClientConfiguration {
 	}
 
 	@Bean
-	ApiClient apiClient(RestClient restClient) {
-		var apiClient = new ApiClient(restClient);
+	ApiClient apiClient(ClientRegistrationRepository clientRegistrations) {
+		var apiClient = new ApiClient(restClient(clientRegistrations));
 		apiClient.setBasePath(apiConfiguration.getUrl());
 		return apiClient;
 	}
 
-	@Bean
-	public RestClient restClient(ClientRegistrationRepository clientRegistrations) {
+	private RestClient restClient(ClientRegistrationRepository clientRegistrations) {
 		OAuth2ClientHttpRequestInterceptor requestInterceptor =
 				new OAuth2ClientHttpRequestInterceptor(authorizedClientManager(clientRegistrations));
 		requestInterceptor.setClientRegistrationIdResolver(request -> "osi2");