Select bottom bottom tab by navigatorId only if it's not selected

This is potentially a breaking change as calling navigator.switchToTab()
won't do anything now if the current tab is already selected.

android/app/src/main/java/com/reactnativenavigation/layouts/BottomTabsLayout.java

         performOnStack(navigatorId, new Task<ScreenStack>() {
             @Override
             public void run(ScreenStack param) {
-                bottomTabs.setCurrentItem(getScreenStackIndex(navigatorId));
+                selectBottomTabByTabIndex(getScreenStackIndex(navigatorId));
             }
         });
     }