Reenable tree confidence intervals

Previously we checked for the presence of num_date confidence on the
first node (nodes[0]). Prior to auspice handling subtrees (arrays of
trees), nodes[0] was guaranteed to be the root node, but this is no
longer the case. Checking a single node wasn't the best approach anyway
as we should check for _any_ node with confidence set, which this
commit now does.

src/actions/recomputeReduxState.js

@@ -356,6 +356,7 @@ const modifyControlsStateViaTree = (state, tree, treeToo, colorings) => {
     coloringsToCheck = Object.keys(colorings);
   }
   let [aaMuts, nucMuts] = [false, false];
+  let num_date_confidence = false; /* flag. Is confidence defined anywhere on the tree? */
   const examineNodes = function examineNodes(nodes) {
     nodes.forEach((node) => {
       /* check colorBys */
@@ -375,6 +376,10 @@ const modifyControlsStateViaTree = (state, tree, treeToo, colorings) => {
         if (keys.length > 1 || (keys.length === 1 && keys[0]!=="nuc")) aaMuts = true;
         if (keys.includes("nuc")) nucMuts = true;
       }
+      /* check num_date confidence */
+      if (!num_date_confidence && getTraitFromNode(node, "num_date", {confidence: true})) {
+        num_date_confidence = true;
+      }
     });
   };
   examineNodes(tree.nodes);
@@ -414,9 +419,8 @@ const modifyControlsStateViaTree = (state, tree, treeToo, colorings) => {
     state.selectedBranchLabel = "clade";
   }
 
-  state.temporalConfidence = getTraitFromNode(tree.nodes[0], "num_date", {confidence: true}) ?
-    {exists: true, display: true, on: false} :
-    {exists: false, display: false, on: false};
+  state.temporalConfidence = {exists: num_date_confidence, display: num_date_confidence, on: false};
+
   return state;
 };