[bugfix] typo in tree visibility property

Oh how TypeScript would have helped!

This bug was found while debugging the ability to show genotype
colorings on both trees (added in the parent commit) where the
visibility of the second tree was `undefined` upon loading, leading to
`createVisibleLegendValues` not considering the second tree and thus
removing legend items which were only observed in the second tree.

Bug introduced ~4 years ago via 391bca4
although its effect was minor (and probably never noticed?)

src/actions/recomputeReduxState.js

@@ -983,7 +983,7 @@ export const createStateFromQueryOrJSONs = ({
     treeNodes: tree.nodes,
     treeTooNodes: treeToo ? treeToo.nodes : undefined,
     visibility: tree.visibility,
-    visibilityToo: treeToo ? treeToo.visibilityToo : undefined
+    visibilityToo: treeToo?.visibility,
   });
 
   /* calculate entropy in view */