Fix Redis cache issue for threshold management

redis.clients.jedis.exceptions.JedisDataException: ERR wrong number of arguments for 'mget' command
	at redis.clients.jedis.Protocol.processError(Protocol.java:127) ~[jedis-2.9.0.jar:?]
	at redis.clients.jedis.Protocol.process(Protocol.java:161) ~[jedis-2.9.0.jar:?]
	at redis.clients.jedis.Protocol.read(Protocol.java:215) ~[jedis-2.9.0.jar:?]
	at redis.clients.jedis.Connection.readProtocolWithCheckingBroken(Connection.java:340) ~[jedis-2.9.0.jar:?]
	at redis.clients.jedis.Connection.getBinaryMultiBulkReply(Connection.java:276) ~[jedis-2.9.0.jar:?]
	at redis.clients.jedis.BinaryJedis.mget(BinaryJedis.java:584) ~[jedis-2.9.0.jar:?]
	at org.nuxeo.ecm.core.redis.contribs.RedisKeyValueStore.lambda$getValuesForKeys$6(RedisKeyValueStore.java:222) ~[nuxeo-core-redis-10.10-HF07.jar:?]
	at org.nuxeo.ecm.core.redis.RedisPoolExecutor.execute(RedisPoolExecutor.java:63) ~[nuxeo-runtime-redis-10.10-HF27.jar:?]
	at org.nuxeo.ecm.core.redis.RedisFailoverExecutor$1.retry(RedisFailoverExecutor.java:62) ~[nuxeo-runtime-redis-10.10-HF27.jar:?]
	at org.nuxeo.ecm.core.redis.retry.Retry.retry(Retry.java:64) ~[nuxeo-runtime-redis-10.10-HF27.jar:?]
	at org.nuxeo.ecm.core.redis.RedisFailoverExecutor.executeWithRetryPolicy(RedisFailoverExecutor.java:57) ~[nuxeo-runtime-redis-10.10-HF27.jar:?]
	at org.nuxeo.ecm.core.redis.RedisFailoverExecutor.execute(RedisFailoverExecutor.java:43) ~[nuxeo-runtime-redis-10.10-HF27.jar:?]
	at org.nuxeo.ecm.core.redis.contribs.RedisKeyValueStore.getValuesForKeys(RedisKeyValueStore.java:222) ~[nuxeo-core-redis-10.10-HF07.jar:?]
	at org.nuxeo.ecm.core.redis.contribs.RedisKeyValueStore.get(RedisKeyValueStore.java:169) ~[nuxeo-core-redis-10.10-HF07.jar:?]
	at org.nuxeo.ai.services.PersistedConfigurationServiceImpl.retrieveAllDescriptors(PersistedConfigurationServiceImpl.java:119) ~[nuxeo-ai-core-2.5.1.jar:?]