RediSearch version < 2.2 with migrate there is no error message

[gam-phon]

Hello,

I know that, RediSearch version >= 2.2 support RedisJson.
When using redis-om with RediSearch version < 2.2 by mistake and running migrate. It did not give any error message, just there are no index. I spent some time to figure it out. if there is an error message it will be much easier to debug.

[simonprickett]

Thanks - I'll see if we can add an error here.