Drop target table before cloning (#1078)

Author: jeremyyeo

dbt-bigquery/.changes/unreleased/Under the Hood-20250509-144421.yaml

@@ -0,0 +1,6 @@
+kind: Under the Hood
+body: Issue drop statement before cloning
+time: 2025-05-09T14:44:21.47639+12:00
+custom:
+    Author: jeremyyeo
+    Issue: "1077"

dbt-bigquery/src/dbt/include/bigquery/macros/materializations/clone.sql

@@ -3,7 +3,8 @@
 {% endmacro %}
 
 {% macro bigquery__create_or_replace_clone(this_relation, defer_relation) %}
+    drop table if exists {{ this_relation }};
     create or replace
       table {{ this_relation }}
-      clone {{ defer_relation }}
+      clone {{ defer_relation }};
 {% endmacro %}