feat: Add fileSelector to the GitFileGenerator to support label-based file match(https://github.com/argoproj/argo-cd/issues/17673)(Alpha)

feat: Add fileSelector to the GitFileGenerator to support label-based file match(https://github.com/argoproj/argo-cd/issues/17673)(Alpha) #26346