1. Sideenus weren't clickable on Android. It seems the order in which
child views were being added to parent controllers, left or right
before center, were affecting the ability to interact with the menus.
I've changed the code to always add them in a specific order: center,
then left, then right.

I believe this closes issue #2835.

  https://github.com/wix/react-native-navigation/issues/2835.

2. On Android, merging options to open a menu works.

  Navigation.mergeOptions(currentComponentId, {
      sideMenu: {
          left: {
              visible: true
          }
      }
  })

But merging options to close it wasn't working.

  Navigation.mergeOptions(currentComponentId, {
      sideMenu: {
          left: {
              visible: false
          }
      }
  })

3. The bottom tabs controller was reserving a margin space for the tabs
when switching from one to another, regardless of its visibility
settings.