Clean untranslated logs (#21956)

Remove the word "<untranslated>" from appearing in the logs. ```release-note NONE ```
2023-01-03 20:14:45 +05:30
--- a/model/utils_test.go
+++ b/model/utils_test.go
@@ -81,6 +81,11 @@ func TestAppError(t *testing.T) {
 	t.Log(appErr.Error())
 }

+func TestAppErrorNoTranslation(t *testing.T) {
+	appErr := NewAppError("TestAppError", NoTranslation, nil, "test error", http.StatusBadRequest)
+	require.Equal(t, "TestAppError: test error", appErr.Error())
+}
+
 func TestAppErrorJunk(t *testing.T) {
 	rerr := AppErrorFromJSON(strings.NewReader("<html><body>This is a broken test</body></html>"))
 	require.Equal(t, "body: <html><body>This is a broken test</body></html>", rerr.DetailedError)