Fix palette icon scaling on Windows, also extend KiBitmapBundle because we use bundles wrong

wxBitmapBundle assumes the smallest bitmap added is the intended "original" size for a particular use case.
And generally that is probably true. However, we re-use icons in some places where we intend for them to start at 16
or start at 24. This is problematic when GetPreferredBitmapSizeFor is called for calculations because it'll return the
16*scale number instead of 24*scale number. So let's just allow passing in a min height restriction to KiBitmapBundle
for when we reuse bitmaps.

common/widgets/bitmap_button.cpp

@@ -336,14 +336,14 @@ void BITMAP_BUTTON::OnPaint( wxPaintEvent& aEvent )
 
     wxPoint drawBmpPos( m_padding, m_padding );
     wxBitmap bmpImg;
-    double scale = KIPLATFORM::UI::GetPixelScaleFactor( this );
+    double scale = KIPLATFORM::UI::GetContentScaleFactor( this );
     wxSize bmSize;
 
     if( m_isToolbarButton )
     {
         int size = Pgm().GetCommonSettings()->m_Appearance.toolbar_icon_size;
-        bmSize = wxSize( size, size );
-        bmpImg = bmp.GetBitmap( bmSize * scale );
+        bmSize = wxSize( size, size ) * scale;
+        bmpImg = bmp.GetBitmap( bmSize );
 
         // wxBitmapBundle::GetBitmap thinks we need this rescaled to match the base size
         if( bmpImg.IsOk() )