Add condition on MongoClientFactoryBean

This commit makes sure that the condition that links a `MongoClient` to
the embedded mongo server kicks in only if `MongoClientFactoryBean` is
also on the classpath.

Previously, only a condition on the mongo driver existed, leading to
`ClassNotFoundException` if Spring Data MongoDB wasn't available.

See gh-6203

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mongo/embedded/EmbeddedMongoAutoConfiguration.java

@@ -63,6 +63,7 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.MutablePropertySources;
 import org.springframework.core.env.PropertySource;
+import org.springframework.data.mongodb.core.MongoClientFactoryBean;
 import org.springframework.util.Assert;
 
 /**
@@ -199,7 +200,7 @@ public class EmbeddedMongoAutoConfiguration {
 	 * {@code embeddedMongoServer} bean.
 	 */
 	@Configuration
-	@ConditionalOnClass(MongoClient.class)
+	@ConditionalOnClass({MongoClient.class, MongoClientFactoryBean.class})
 	protected static class EmbeddedMongoDependencyConfiguration
 			extends MongoClientDependsOnBeanFactoryPostProcessor {