Json Fail: tileInstance's `t`

[Cammin]

I found a json deserialization failure: The t value of a tile instance in a layer instance's autoLayerTiles can be null.

The json deserializer expects an int for the c# schema, but it's possible to save the project with a null value in it, and so it errors out.

I don't know the reproduction steps, but it may be from removing intgrid values/rules/tilesets from the project.

It's possible that this can happen because of this "error" visual: