Fix tree node check states not being updated

This commit fixes a bug where the check states of tree nodes were not
correctly updated upon selecting predefined groups like "Standard",
"Strict", "None" and "All".

It resolves the issue by manually triggering of updates for mutated
array containing selected scripts.

It enhances test coverage to prevent regression and verify the correct
behavior of state updates.

This bug was introduced in commit
4995e49c46, which optimized reactivity by
removing deep state tracking.

tests/unit/shared/Stubs/UserSelectionStub.ts

@@ -1,15 +1,13 @@
 import { IUserSelection } from '@/application/Context/State/Selection/IUserSelection';
 import { SelectedScript } from '@/application/Context/State/Selection/SelectedScript';
 import { IScript } from '@/domain/IScript';
-import { IEventSource } from '@/infrastructure/Events/IEventSource';
-import { EventSource } from '@/infrastructure/Events/EventSource';
 import { StubWithObservableMethodCalls } from './StubWithObservableMethodCalls';
+import { EventSourceStub } from './EventSourceStub';
 
 export class UserSelectionStub
   extends StubWithObservableMethodCalls<IUserSelection>
   implements IUserSelection {
-  public readonly changed: IEventSource<readonly SelectedScript[]> = new EventSource<
-  readonly SelectedScript[]>();
+  public readonly changed = new EventSourceStub<readonly SelectedScript[]>();
 
   public selectedScripts: readonly SelectedScript[] = [];
 
@@ -22,6 +20,11 @@ export class UserSelectionStub
     return this;
   }
 
+  public triggerSelectionChangedEvent(scripts: readonly SelectedScript[]): this {
+    this.changed.notify(scripts);
+    return this;
+  }
+
   public areAllSelected(): boolean {
     throw new Error('Method not implemented.');
   }