RedisIndexedSessionRepository resolveDatabase method not support redisson client

Describe the bug
"The RedisIndexedSessionRepository has a method called resolveDatabase() that retrieves the Redis database currently in use. However, when using Redisson, it always returns DEFAULT_DATABASE. This is because Redisson implements a different RedisConnectionFactory named org.redisson.spring.data.connection.RedissonConnectionFactory

	private int resolveDatabase() {
		if (ClassUtils.isPresent("io.lettuce.core.RedisClient", null)
				&& getRedisConnectionFactory() instanceof LettuceConnectionFactory) {
			return ((LettuceConnectionFactory) getRedisConnectionFactory()).getDatabase();
		}
		if (ClassUtils.isPresent("redis.clients.jedis.Jedis", null)
				&& getRedisConnectionFactory() instanceof JedisConnectionFactory) {
			return ((JedisConnectionFactory) getRedisConnectionFactory()).getDatabase();
		}
		return RedisIndexedSessionRepository.DEFAULT_DATABASE;
	}

Start in RedisIndexedSessionRepository.resolveDatabase() and inspect how the repository identifies LettuceConnectionFactory and JedisConnectionFactory. Compare that logic with RedissonConnectionFactory and verify that the configured Redis database is returned instead of DEFAULT_DATABASE; add or update coverage if the surrounding tests expose this method's behavior.