Mini-drop duplicated code

[borisovcode]

  Widget createScreenFor(int screenIndex, bool showNavBarExample) {
    switch (screenIndex) {
      // duplicated code for "default" case
      case 0:
        return ComponentScreen(showNavBottomBar: showNavBarExample);
      ...
      default:
        return ComponentScreen(showNavBottomBar: showNavBarExample);
    }
  }

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[domesticmouse]

We need you to sign a CLA before we further review this PR. Thanks!

[domesticmouse]

Sorry @borisovcode, we can't accept PRs without a signed CLA. Feel free to re-open once you have signed a CLA. Thanks!