Add new type handling for external shallow clones. Much like managed shallow clones, we need to collapse the type to something that dbt knows how to handle.
Checklist
[x] I have run this code in development and it appears to resolve the stated issue
[x] This PR includes tests, or tests are not required/relevant for this PR
[x] I have updated the CHANGELOG.md and added information about my change to the "dbt-databricks next" section.
Description
Add new type handling for external shallow clones. Much like managed shallow clones, we need to collapse the type to something that dbt knows how to handle.
Checklist
CHANGELOG.mdand added information about my change to the "dbt-databricks next" section.