Fix Direct2D graphics context after wxPenInfo changes

At least in wxMSW wxPen::GetStipple() returns a non-null (but invalid)
bitmap even when pen style is not wxPENSTYLE_STIPPLE, so don't test for
this bitmap when creating a wxGraphicsPen from a wxPen but for the style
directly.

This avoids using this invalid bitmap later in D2D code, where it
resulted in assert failures.

Also add a similar style test before calling wxPen::GetDashes() for
consistency, even if it doesn't seem to be strictly necessary.

See https://github.com/wxWidgets/wxWidgets/pull/553

Closes #17958.

src/common/graphcmn.cpp

@@ -836,12 +836,18 @@ wxGraphicsPen wxGraphicsContext::CreatePen(const wxPen& pen) const
                                 .Cap(pen.GetCap())
                                 ;
 
+    if ( info.GetStyle() == wxPENSTYLE_USER_DASH )
+    {
         wxDash *dashes;
         if ( int nb_dashes = pen.GetDashes(&dashes) )
             info.Dashes(nb_dashes, dashes);
+    }
 
+    if ( info.GetStyle() == wxPENSTYLE_STIPPLE )
+    {
         if ( wxBitmap* const stipple = pen.GetStipple() )
             info.Stipple(*stipple);
+    }
 
     return DoCreatePen(info);
 }