Add wxBitmap::GetDIPSize() and use it in wxBitmapBundleImplArt

This fixes the problem with wrong standard bitmaps size when using high
DPI for the main monitor with wxMSW, as GetScaledSize() used here since
31f2892200 (Avoid bitmap scaling in wxArtProvider::GetBitmapBundle(),
2021-12-17) was not the right function to use there.

Closes #19331.

src/common/artprov.cpp

@@ -193,7 +193,7 @@ private:
         // necessary, so use GetScaledSize() and not GetSize().
         const wxBitmap bitmap = wxArtProvider::GetBitmap(id, client);
         if ( bitmap.IsOk() )
-            return bitmap.GetScaledSize();
+            return bitmap.GetDIPSize();
 
         // We really need some default size, so just return this hardcoded
         // value if all else fails -- what else can we do.

src/common/bmpbase.cpp

@@ -220,6 +220,11 @@ double wxBitmapBase::GetScaleFactor() const
     return 1.0;
 }
 
+wxSize wxBitmapBase::GetDIPSize() const
+{
+    return GetSize() / GetScaleFactor();
+}
+
 #ifdef wxHAS_DPI_INDEPENDENT_PIXELS
 
 double wxBitmapBase::GetScaledWidth() const

src/msw/bitmap.cpp

@@ -1385,6 +1385,11 @@ double wxBitmap::GetScaleFactor() const
     return GetBitmapData()->m_scaleFactor;
 }
 
+wxSize wxBitmap::GetDIPSize() const
+{
+    return GetSize() / GetScaleFactor();
+}
+
 double wxBitmap::GetScaledWidth() const
 {
     return GetWidth();