vtgate: Allow more errors for the warning check (#14421)

Signed-off-by: Dirkjan Bussink <[email protected]>

go/test/endtoend/vtgate/errors_as_warnings/main_test.go

@@ -141,9 +141,9 @@ func TestScatterErrsAsWarns(t *testing.T) {
 			utils.Exec(t, mode.conn, fmt.Sprintf("set workload = %s", mode.m))
 
 			utils.AssertMatches(t, mode.conn, query1, `[[INT64(4)]]`)
-			assertContainsOneOf(t, mode.conn, showQ, "no valid tablet", "no healthy tablet", "mysql.sock: connect: no such file or directory")
+			assertContainsOneOf(t, mode.conn, showQ, "operation not allowed in state SHUTTING_DOWN", "no valid tablet", "no healthy tablet", "mysql.sock: connect: no such file or directory")
 			utils.AssertMatches(t, mode.conn, query2, `[[INT64(4)]]`)
-			assertContainsOneOf(t, mode.conn, showQ, "no valid tablet", "no healthy tablet", "mysql.sock: connect: no such file or directory")
+			assertContainsOneOf(t, mode.conn, showQ, "operation not allowed in state SHUTTING_DOWN", "no valid tablet", "no healthy tablet", "mysql.sock: connect: no such file or directory")
 
 			// invalid_field should throw error and not warning
 			_, err = mode.conn.ExecuteFetch("SELECT /*vt+ PLANNER=Gen4 SCATTER_ERRORS_AS_WARNINGS */ invalid_field from t1;", 1, false)