Imported classic skins default to wide

Steps to Reproduce:

1. Load up Minecraft Bedrock Edition on a device that can hold image files.
2. Go to Dressing Room and create an imported classic skin with a slim player model.
3. Save and close Minecraft.
4. Reopen Minecraft.

Observed Results:

1. Player model for imported classic skin has defaulted to wide.

Expected Results:

1. Player model for imported classic skin is still set to slim.