Fix Redshift parenthesized single-column SORTKEY

sqlmesh/core/engine_adapter/redshift.py

@@ -295,7 +295,12 @@ def _to_identifier_if_string(expression: exp.Expr) -> exp.Expr:
 
             sortkey = table_properties.get("SORTKEY")
             if sortkey:
-                sortkey_expressions = sortkey.expressions if sortkey.expressions else [sortkey]
+                if isinstance(sortkey, (exp.Tuple, exp.Array)):
+                    sortkey_expressions = sortkey.expressions
+                elif isinstance(sortkey, exp.Paren):
+                    sortkey_expressions = [sortkey.unnest()]
+                else:
+                    sortkey_expressions = [sortkey]
                 properties.append(
                     exp.SortKeyProperty(
                         this=[

tests/core/engine_adapter/test_redshift.py

@@ -167,7 +167,7 @@ def test_create_table_physical_properties_from_model_definition(
     physical_properties (
         diststyle = key,
         distkey = "id_file",
-        sortkey = "batch_time"
+        sortkey = ("batch_time")
     )
 );
 SELECT id_file::INT, batch_time::TIMESTAMP;