chore(*): Makes event property mandatory

Author: 3phase

projects/igniteui-angular/src/lib/grids/grid-base.directive.ts

@@ -2858,7 +2858,7 @@ export class IgxGridBaseDirective extends DisplayDensityBase implements
             this.summaryService.clearSummaryCache(args);
         });
 
-        this.transactions.onStateUpdate.pipe(destructor).subscribe((event?: StateUpdateEvent) => {
+        this.transactions.onStateUpdate.pipe(destructor).subscribe((event: StateUpdateEvent) => {
             let actions = [];
             if (event.origin === TransactionEventOrigin.REDO) {
                 actions = event.actions ? event.actions.filter(x => x.transaction.type === TransactionType.DELETE) : [];

projects/igniteui-angular/src/lib/grids/tree-grid/tree-grid.component.ts

@@ -353,7 +353,7 @@ export class IgxTreeGridComponent extends IgxGridBaseDirective implements GridTy
             this.loadChildrenOnRowExpansion(args);
         });
 
-        this.transactions.onStateUpdate.pipe(takeUntil<any>(this.destroy$)).subscribe((event?: StateUpdateEvent) => {
+        this.transactions.onStateUpdate.pipe(takeUntil<any>(this.destroy$)).subscribe((event: StateUpdateEvent) => {
             let actions = [];
             if (event.origin === TransactionEventOrigin.REDO) {
                 actions = event.actions ? event.actions.filter(x => x.transaction.type === TransactionType.DELETE) : [];

projects/igniteui-angular/src/lib/services/transaction/igx-transaction.ts

@@ -48,7 +48,7 @@ export class IgxTransactionService<T extends Transaction, S extends State> exten
             const actions = [{ transaction, recordRef }];
             this._undoStack.push(actions);
             this._redoStack = [];
-            this.onStateUpdate.emit({ origin: TransactionEventOrigin.ADD, actions: actions });
+            this.onStateUpdate.emit({ origin: TransactionEventOrigin.ADD, actions });
         }
     }