message: Fix overflow in scroll-to-bottom
  ## PR Checklist
  * [x] Closes
  * [x] CLA signed.
  * [ ] Tests added/passed
  * [ ] Documentation updated.
  * [ ] Schema updated.
  * [ ] I've discussed this with core contributors already.
diff: @@ -379,7 +379,7 @@ namespace winrt::TerminalApp::implementation
  co_await winrt::resume_foreground(control.Dispatcher());
  const auto currentOffset = control.GetScrollOffset();
  - control.ScrollViewport(currentOffset + delta);
  + control.ScrollViewport(::base::ClampAdd(currentOffset, delta));
  }
  // Method Description:
  