fixed the bug that settings backButton color dynamically does not working (#4513)

lib/ios/RNNNavigationControllerPresenter.m

 		[navigationController rnn_setNavigationBarLargeTitleVisible:newOptions.topBar.largeTitle.visible.get];
 	}
 	
-	if (newOptions.topBar.backButton.icon.hasValue) {
+	if (newOptions.topBar.backButton.icon.hasValue || newOptions.topBar.backButton.showTitle.hasValue || newOptions.topBar.backButton.color.hasValue || newOptions.topBar.backButton.title.hasValue) {
 		[navigationController rnn_setBackButtonIcon:[newOptions.topBar.backButton.icon getWithDefaultValue:nil] withColor:[newOptions.topBar.backButton.color getWithDefaultValue:nil] title:[newOptions.topBar.backButton.showTitle getWithDefaultValue:YES] ? [newOptions.topBar.backButton.title getWithDefaultValue:nil] : @""];
 		
 	}