New world creation screen allows users to change cheat gamerules without disabling achievements

Steps to Reproduce:

1. Enable the new world creation screen;
2. Enable cheats;
3. Change any gamerules that are within the cheats section (except for Education Edition);
4. Disable cheats;
5. Create world.

Observed Results:
Achievements are still enabled upon joining the world.

Expected Results:
Enabling cheats for the first time displays a warning pop-up (MCPE-151914) and, after confirmation, achievements are disabled.

Notes: