win: Add file association for .jxl
Updated shell extension to v1.2.4d to add file association for .jxl, and added .jxl to MSIX manifest.
@rempt Please upload krita-nsis-v1.2.4d.zip from https://github.com/alvinhochun/KritaShellExtension/releases/tag/v1.2.4d to files-kde-org.