Fix Vega expressions - replace JavaScript reduce() with Vega sum() and pluck() functions

Co-authored-by: danmarshall <11507384+danmarshall@users.noreply.github.com>

Author: Copilot

packages/web-deploy/json/persona-budget.idoc.json

@@ -118,15 +118,15 @@
             "type": "number",
             "initialValue": 0,
             "calculation": {
-                "vegaExpression": "data('adjustedBudgetData') ? data('adjustedBudgetData').reduce((sum, d) => sum + d.adjustedBudget, 0) : 0"
+                "vegaExpression": "data('adjustedBudgetData') ? sum(pluck(data('adjustedBudgetData'), 'adjustedBudget')) : 0"
             }
         },
         {
             "variableId": "totalSpent",
             "type": "number",
             "initialValue": 0,
             "calculation": {
-                "vegaExpression": "data('adjustedBudgetData') ? data('adjustedBudgetData').reduce((sum, d) => sum + d.spent, 0) : 0"
+                "vegaExpression": "data('adjustedBudgetData') ? sum(pluck(data('adjustedBudgetData'), 'spent')) : 0"
             }
         },
         {