DataGrid with template columns causes crash when scrolling

* Only Net 4.7.2 (required since the application is a Visual Studio extension)
* Windows version: 20H2 19042.1237
* Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes
* Is this bug related specifically to tooling in Visual Studio (e.g. XAML Designer, Code editing, etc...)? No

**Problem description:**
Application crash when scrolling a DataGrid with template columns. (ArgumentNullException in the DataGridItemAutomationPeer)

**Actual behavior:**
Application crash, stack trace can be found here: https://github.com/dotnet/ResXResourceManager/issues/430

**Expected behavior:**
Scrolling works without crashing the application

**Minimal repro:**
Steps how to reproduce can be found here: https://github.com/dotnet/ResXResourceManager/issues/430