models: cards: allow singletons to be assigned to members and labelIds

If we need to set only one member or one label, the data provided will
not give us an array, but the only element as a string.
We need to detect that and convert the parameter into an array.

models/cards.js

@@ -1457,7 +1457,10 @@ if (Meteor.isServer) {
       });
     }
     if (req.body.hasOwnProperty('labelIds')) {
-      const newlabelIds = req.body.labelIds;
+      let newlabelIds = req.body.labelIds;
+      if (_.isString(newlabelIds)) {
+        newlabelIds = [newlabelIds];
+      }
       Cards.direct.update({
         _id: paramCardId,
         listId: paramListId,
@@ -1515,7 +1518,10 @@ if (Meteor.isServer) {
         {$set: {customFields: newcustomFields}});
     }
     if (req.body.hasOwnProperty('members')) {
-      const newmembers = req.body.members;
+      let newmembers = req.body.members;
+      if (_.isString(newmembers)) {
+        newmembers = [newmembers];
+      }
       Cards.direct.update({_id: paramCardId, listId: paramListId, boardId: paramBoardId, archived: false},
         {$set: {members: newmembers}});
     }