message: Installer - fix missing UIRef
diff: <Icon Id="app.ico" SourceFile="$(var.PublishFolder)\$(var.AppExecutableName)" />
  <UIRef Id="Custom_WixUI_InstallDir" />
  + <UIRef Id="WixUI_ErrorProgressText" />
  <WixVariable Id="WixUIDialogBmp" Value="assets\background.bmp" />
  <WixVariable Id="WixUIBannerBmp" Value="assets\banner.bmp" />
  