Don't use KIO in core when building for Sailfish

2 jobs for master in 8 minutes and 2 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #20133
linux kf5-qt5 qt5.12

00:07:10

34.0%
passed #20134
windows
windows kf5-qt5 qt5.13

00:08:01