Removing the tls_verify_client flag from feast cli for offline server

[lokeshrangineni]

There is a misunderstanding of the tls_verify_client flag for offline server. We need this flag if we need to support mTLS and at the moment we are planning to support only TLS. We should not expose this field to feast CLI rather disable at the Apache Flight server level. In case if we would like to support mTLS then we can make the necessary changes on the client and server side.