Warn about autowrapped labels in containers

[YuriSizov]

Adds a warning for cases like #83546, until we fix the sizing model for autowrapped nodes.

[akien-mga]

Seems to work well on a scene which I spent 1 hour debugging yesterday to find the problem:

So this will be quite useful for others too I believe.

[KoBeWi]

You can also set EXPAND_FILL and it will work too (depending on the container). Minimum size is not always a requirement.

[YuriSizov]

You can also set EXPAND_FILL and it will work too (depending on the container). Minimum size is not always a requirement.

This is not a guarantee. The issue comes from minimum size computations, whereas the size flags are only considered when fitting children.

[akien-mga]

Thanks!