chore: skip create_trigger/add_trigger test on PG 14-15

The test includes a view whose pg_get_viewdef() output differs between
PG 15 (table-qualified columns) and PG 16+ (unqualified), causing
fingerprint mismatches.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: tianzhou

testutil/skip_list.go

@@ -36,6 +36,9 @@ var skipListPG14_15 = []string{
 	// Index tests - fingerprint includes view definitions
 	"create_index/drop_index",
 
+	// Trigger tests - fingerprint includes view definitions
+	"create_trigger/add_trigger",
+
 	// Migration tests - include views and materialized views
 	"migrate/v4",
 	"migrate/v5",