message: Allow single cell selection with Shift+Click
  Closes
diff: @@ -1288,7 +1288,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
  _terminal->SetSelectionEnd(terminalPosition, mode);
  _selectionNeedsToBeCopied = true;
  }
  - else if (mode == ::Terminal::SelectionExpansionMode::Cell)
  + else if (mode == ::Terminal::SelectionExpansionMode::Cell && !shiftEnabled)
  {
  // Single Click: reset the selection and begin a new one
  _terminal->ClearSelection();
  