Merchants zone setup

**Issue**
Please emphasize in the [Data Domain and Asset Mapping](https://github.com/GoogleCloudPlatform/dataplex-labs/tree/main/data-mesh-banking-labs#13-data-domains-and-asset-mapping) _written description_ that in the terraform setup the curated and data product are merged to one for Merchants and Credit Card Transaction Domain. (This is only a small fineprint in the [domain structure diagram png](https://github.com/GoogleCloudPlatform/dataplex-labs/blob/main/data-mesh-banking-labs/setup/resources/imgs/Domain-structure.png) and thus not searchable.)

**Why is this a problem?**
When trying to reuse the exact steps in [Lab 3](https://github.com/GoogleCloudPlatform/dataplex-labs/tree/main/data-mesh-banking-labs/lab3-data-curation) for the Merchants Domain this will fail given the merged zones, so it's important to note that the terraform setup is different so one can correct for the initial setup.