(core) Adding traceback to trigger formulas

Summary:
Traceback is available on the Creator Panel in the formula editor. It is evaluated the same way as for normal formulas.
In case when the traceback is not available, only the error name is displayed with information that traceback is not available.
Cell with an error, when edited, shows the previous valid value that was used before the error happened (or None for new rows).
Value is stored inside the RaisedException object that is stored in a cell.

Test Plan: Created tests

Reviewers: alexmojaki

Reviewed By: alexmojaki

Subscribers: alexmojaki, dsagal

Differential Revision: https://phab.getgrist.com/D3033

app/client/ui/FieldConfig.ts

@@ -158,7 +158,8 @@ function createFormulaErrorObs(owner: MultiHolder, gristDoc: GristDoc, origColum
   function countErrors() {
     if (owner.isDisposed()) { return; }
     const tableData = gristDoc.docData.getTable(origColumn.table.peek().tableId.peek());
-    if (tableData && origColumn.isRealFormula.peek()) {
+    const isFormula = origColumn.isRealFormula.peek() || origColumn.hasTriggerFormula.peek();
+    if (tableData && isFormula) {
       const colId = origColumn.colId.peek();
       const numCells = tableData.getColValues(colId)?.length || 0;
       const numErrors = tableData.countErrors(colId) || 0;