Stop override tabBarItem by parent layouts (#4470)

* Stop override tabBarItem by parent layouts

* Fix unit

lib/ios/RNNNavigationController.m

 	[self.options overrideOptions:options];
 }
 
-- (UITabBarItem *)tabBarItem {
-	return self.viewControllers.firstObject.tabBarItem;
-}
-
 - (UIInterfaceOrientationMask)supportedInterfaceOrientations {
 	return self.getCurrentChild.supportedInterfaceOrientations;
 }

lib/ios/RNNSideMenuChildVC.m

 	[self.options overrideOptions:options];
 }
 
-- (UITabBarItem *)tabBarItem {
-	return self.child.tabBarItem;
-}
-
 - (void)bindChildViewController:(UIViewController<RNNLayoutProtocol>*)child {
 	self.child = child;
 	[self addChildViewController:self.child];

lib/ios/RNNSideMenuController.m

 	}
 }
 
-- (UITabBarItem *)tabBarItem {
-	return self.center.tabBarItem;
-}
-
 - (void)onChildWillAppear {
 	[_presenter applyOptions:self.resolveOptions];
 	[((UIViewController<RNNParentProtocol> *)self.parentViewController) onChildWillAppear];

lib/ios/ReactNativeNavigationTests/RNNNavigationControllerTest.m

 	XCTAssertFalse(self.uut.navigationController.navigationBar.clipsToBounds);
 }
 
-- (void)testTabBarItemShouldReturnFirstChildTabBarItem {
-	XCTAssertEqual(self.uut.tabBarItem, self.uut.childViewControllers.firstObject.tabBarItem);
-}
-
 - (void)testSupportedOrientationsShouldReturnCurrentChildSupportedOrientations {
 	XCTAssertEqual(self.uut.supportedInterfaceOrientations, self.uut.getCurrentChild.supportedInterfaceOrientations);
 }