[MCPE-35692] World deletion after loss of power

Update on this issue by [Mojang] Mega_Spud (Jay Wells)

^12-Nov-18 - For those still having issues with their worlds not showing in the world list - In many cases the actual save data is still present on the device, so the advice from the developers in not to uninstall or delete the game data, as we are working on a fix that should enable the saves to be recognised and show in the list again correctly.

I was on my Xbox One Minecraft Bedrock Edition world when my power went out and when I logged back in the next day when my power returned my world was gone, deleted. This is on v1.5.0, and a survival multiplayer world