Consider MongoOperationsSessionRepository when checking for duplicates

See gh-9552

Author: wilkinsona

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/SessionAutoConfiguration.java

@@ -113,6 +113,8 @@ public void checkAvailableImplementations() {
 					"org.springframework.session.hazelcast.HazelcastSessionRepository");
 			addCandidate(candidates,
 					"org.springframework.session.jdbc.JdbcOperationsSessionRepository");
+			addCandidate(candidates,
+					"org.springframework.session.data.mongo.MongoOperationsSessionRepository");
 			addCandidate(candidates,
 					"org.springframework.session.data.redis.RedisOperationsSessionRepository");
 			StoreType storeType = this.sessionProperties.getStoreType();