Prepare test data for `cardano/assets` endpoint

[Mr-Leshiy]

Summary

Prepare a test data including cardano native assets info so it will be possible to test cardano/assets endpoint.

Description

Prepare a test data including cardano native assets info so it will be possible to test cardano/assets endpoint.
For the preprod and mainnet networks.

The most recent version of the cardano/assets endpoint located here #2119