Add changed control into the Climatic > Prfepare > Summary dialog

[rdstern]

@N-thony and @lilyclements I hope this is a simple change now?

Here is the climatic summary dialog.

I trust it is using the same code, for most bits, as the Prepare > Data Reshape > Summary dialog?

So please could you include the new enabled Drop Uniused Levels control? It should also be ticked by default here? Please report if it seems complicated? That may mean we need to think harder first.

[lilyclements]

@rdstern yes - just checked and this is a simple change. Should be as simple as enabling the checkbox, and setting drop = FALSE when unchecked.