Raise a proper error message if the filename for SaveAs does contain the .rtd extension

[peterjamesnugent]

Description:

When using the SaveAs command with an Exectute component - if the filename does contain the .rtd extension is produces the following error:

1. This component failed to run properly.

• Error: Error HRESULT E_FAIL has been returned from a call to a COM component.
• Occured in BH.Adapter.Robot.RobotAdapter.RunCommand(SaveAs command)
  called from BH.Adapter.Robot.RobotAdapter.Execute(IExecuteCommand command, ActionConfig actionConfig)
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Steps to reproduce:

See above.

Expected behaviour:

The adapter should raise an error instructing the user to provide a filepath with the correct extension.

Test file(s):