fix: in iteration node picker may show the wrong var type (#5435)

web/app/components/workflow/nodes/_base/components/variable/utils.ts

@@ -344,8 +344,6 @@ export const getVarType = ({
     }
     if (valueSelector[1] === 'index')
       return VarType.number
-
-    return VarType.string
   }
   const isSystem = isSystemVar(valueSelector)
   const startNode = availableNodes.find((node: any) => {