NullReferenceException is thrown when using Add Reports from Folder option in Adressables Report window

Steps to reproduce:

1. Open the attached project
2. In the Addressables Groups window, trigger a build (Build -> New Build -> Default Build Script)
3. In the Addressables Report window, press the + button
4. Select the Add Reports from Folder option
5. Confirm the folder location in the file browser
6. Observe the Console window

Actual results: NullReferenceException is thrown, and the reports are not added

Expected results: NullReferenceExceptions are not thrown when trying to add the folder with reports

Reproducible with versions: 2.9.1 (6000.0.79f1), 4.0.1 (6000.0.79f1, 6000.7.0a5)

Tested on (OS): macOS 26.6.2, Ubuntu 24

Full error message:

• NullReferenceException: Object reference not set to an instance of an object
  UnityEditor.AddressableAssets.BuildReportVisualizer.BuildReportListView.BuildLayoutIsValid (System.String packageVersion) (at ./Library/PackageCache/com.unity.addressables@37a0b4bd16b0/Editor/BuildReportVisualizer/BuildReportListView.cs:208)
  UnityEditor.AddressableAssets.BuildReportVisualizer.BuildReportListView.BuildLayoutIsValid (UnityEditor.AddressableAssets.Build.Layout.BuildLayout layout) (at ./Library/PackageCache/com.unity.addressables@37a0b4bd16b0/Editor/BuildReportVisualizer/BuildReportListView.cs:204)
  UnityEditor.AddressableAssets.BuildReportVisualizer.BuildReportListView.AddReportFromFile (System.String filePath, UnityEngine.UIElements.ListView listView, System.Boolean logWarning, System.Boolean shouldRebuild) (at ./Library/PackageCache/com.unity.addressables@37a0b4bd16b0/Editor/BuildReportVisualizer/BuildReportListView.cs:242)
  UnityEditor.AddressableAssets.BuildReportVisualizer.BuildReportListView.AddReportFromFile (System.String filePath) (at ./Library/PackageCache/com.unity.addressables@37a0b4bd16b0/Editor/BuildReportVisualizer/BuildReportListView.cs:197)
  UnityEditor.AddressableAssets.BuildReportVisualizer.MainToolbar+<>c_DisplayClass4_0.<CreateGUI>b_2 (UnityEngine.UIElements.DropdownMenuAction x) (at ./Library/PackageCache/com.unity.addressables@37a0b4bd16b0/Editor/BuildReportVisualizer/MainToolbar.cs:76)
  UnityEngine.UIElements.DropdownMenuAction.Execute () (at /Users/bokken/build/output/unity/unity/Modules/UIElements/Core/DropdownMenu.cs:224)
  UnityEditor.UIElements.EditorMenuExtensions+<>c_DisplayClass0_0.<PrepareMenu>b_0 () (at /Users/bokken/build/output/unity/unity/Editor/Mono/UIElements/EditorMenuExtensions.cs:36)
  UnityEditor.GenericMenu.CatchMenu (System.Object userData, System.String[] options, System.Int32 selected) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUI/GenericMenu.cs:164)
  UnityEngine.StackTraceUtility:ExtractStringFromExceptionInternal(Object, String&, String&) (at /Users/bokken/build/output/unity/unity/Runtime/Export/Scripting/StackTrace.cs:50)