dimension_linear always failed with '<unknown>.AddDimLinear' on the COM
backend — pywin32's dynamic dispatch error for a method that does not
exist: the AutoCAD ActiveX API has no AddDimLinear. AddDimRotated takes
the same arguments (XLine1Point, XLine2Point, DimLineLocation,
RotationAngle), so the call site only changes the method name.
Adds a mocked regression test asserting AddDimRotated is called with
the exact point/rotation arguments and AddDimLinear never is.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>