Also make snapshots when removing options

So we don't have situations where we can't undo a
selection that occurred from removing the second last
option.

commonUI/src/commonMain/kotlin/ch/dissem/yaep/ui/common/App.kt

@@ -141,6 +141,7 @@ fun PuzzleGrid(
                             .weight(1f),
                         options = options,
                         onOptionRemoved = {
+                            grid.snapshot()
                             item.options.remove(it)
                             row.cleanupOptions()
                         },