docs: Update dbt.mdx (#8680)

Add description from dbt manifest

docs/pages/guides/dbt.mdx

@@ -263,6 +263,7 @@ cubes:
       - name: "{{ column.name }}"
         sql: "{{ column.sql }}"
         type: "{{ column.type }}"
+        description: "{{ column.description }}"
         meta:
           source: dbt
       {% endfor %}
@@ -361,4 +362,4 @@ of the REST API.
 [link-dbt-docs-columns]: https://docs.getdbt.com/reference/resource-properties/columns
 [link-dbt-materializations]: https://docs.getdbt.com/docs/build/materializations
 [link-smart-open]: https://pypi.org/project/smart-open/
-[link-boto3]: https://boto3.amazonaws.com/v1/documentation/api/latest/guide/s3-examples.html
+[link-boto3]: https://boto3.amazonaws.com/v1/documentation/api/latest/guide/s3-examples.html