Remove GetDPIScaleFactor from wxDC and wxGraphicsContext

This reverts most of the changes from ee2b02614e (Add GetDPIScaleFactor to wxDC
and wxGraphicsContext, 2022-04-16).

This is not supposed to be used to scale pixels, FromDIP will be added instead.

Temporary use scale=1 in the drawing sample until FromDIP is added.

include/wx/dc.h

@@ -539,8 +539,6 @@ public:
 
     virtual double GetContentScaleFactor() const { return m_contentScaleFactor; }
 
-    virtual double GetDPIScaleFactor() const { return 1.0; }
-
 #ifdef __WXMSW__
     // Native Windows functions using the underlying HDC don't honour GDI+
     // transformations which may be applied to it. Using this function we can
@@ -829,9 +827,6 @@ public:
     double GetContentScaleFactor() const
         { return m_pimpl->GetContentScaleFactor(); }
 
-    double GetDPIScaleFactor() const
-        { return m_pimpl->GetDPIScaleFactor(); }
-
     // Right-To-Left (RTL) modes
 
     void SetLayoutDirection(wxLayoutDirection dir)