remove superfluous need_drop_temp variable and add temp_relation to t…

…o_drop within if-statement

dbt/include/duckdb/macros/materializations/incremental.sql

@@ -46,7 +46,7 @@
       {% set temp_relation = temp_relation.incorporate(path=adapter.get_temp_relation_path(this)) %}
       {% do run_query(create_schema(temp_relation)) %}
       -- then drop the temp relation after we insert the incremental data into the target relation
-      {% set need_drop_temp = True %}
+      {% do to_drop.append(temp_relation) %}
     {% endif %}
     {% if language == 'python' %}
       {% set build_python = create_table_as(False, temp_relation, compiled_code, language) %}
@@ -85,10 +85,6 @@
       {% do to_drop.append(backup_relation) %}
   {% endif %}
 
-  {% if need_drop_temp %}
-      {% do to_drop.append(temp_relation) %}
-  {% endif %}
-
   {% set should_revoke = should_revoke(existing_relation, full_refresh_mode) %}
   {% do apply_grants(target_relation, grant_config, should_revoke=should_revoke) %}