Release: Update installer graphic for 4.4

Also switch to .png format for better compression.

Pull Request: https://projects.blender.org/blender/blender/pulls/137471

build_files/cmake/packaging.cmake

@@ -107,7 +107,7 @@ if(WIN32)
 
   set(CPACK_WIX_TEMPLATE ${CMAKE_SOURCE_DIR}/release/windows/installer_wix/WIX.template)
   set(CPACK_WIX_UI_BANNER ${CMAKE_SOURCE_DIR}/release/windows/installer_wix/WIX_UI_BANNER.bmp)
-  set(CPACK_WIX_UI_DIALOG ${CMAKE_SOURCE_DIR}/release/windows/installer_wix/WIX_UI_DIALOG.bmp)
+  set(CPACK_WIX_UI_DIALOG ${CMAKE_SOURCE_DIR}/release/windows/installer_wix/WIX_UI_DIALOG.png)
   set(CPACK_WIX_EXTRA_SOURCES ${CMAKE_SOURCE_DIR}/release/windows/installer_wix/WixUI_Blender.wxs)
   set(CPACK_WIX_UI_REF "WixUI_Blender")
   set(CPACK_WIX_LIGHT_EXTRA_FLAGS -dcl:medium)