[Feature] Allow Databricks to define database variable

### Is there an existing feature request for this?

- [X] I have searched the existing issues

### Describe the Feature

Currently the package will exclude the `shopify_database` from being defined if the destination is Databricks. This was appropriate in the past. However, since the addition of the Databricks Unit Catalog there is now a concept of a database structure that some Databricks users may want/need to take advantage of.

This feature is to remove `databricks` from the exclusion conditional noted below. Please be aware we will still need to include `spark` as not all spark clusters allow Unity Catalogs. That is a Databricks specific feature.

https://github.com/fivetran/dbt_shopify_source/blob/008a2c94f09cbf256885c66c4a636f0081ef8e97/models/src_shopify.yml#L6

### Describe alternatives you've considered

There are no real alternatives other than a Databricks user not leveraging the Unity Catalog for database structures.

### Are you interested in contributing this feature?

- [ ] Yes.
- [ ] Yes, but I will need assistance and will schedule time during your [office hours](https://calendly.com/fivetran-solutions-team/fivetran-solutions-team-office-hours) for guidance.
- [ ] No.

### Anything else?

_No response_