Wrong behaviour for imported into the policy schemas with nested schemas during publish

[kirill-tolochko]

Problem description

If user imports in the policy schema with nested schema by messageId, there is an error during publish.

Step to reproduce

1. Create schema with nested schema, publish it.
2. Import this schema in the policy by messageId
3. Publish the policy

Expected behavior

Everything is ok

Actual behavior

There is an uninformative error during publish