Log Message:
kitemmodels: update to 5.108.0

5.99
  Remove obsolete classes from the Qt 6 build
5.100
  Also fix kconcatenaterows_qml test for static builds
  Fix ksortfilterproxymodel_qml test for static builds
5.101
  Also remove the custom target in BUILD_TESTING
  Make use of ecm_add_qml_module()
5.104
  KDescendantProxyModel: Do not remove indexes from mapping before announcing
  the removal
5.107
  Preserve numeric sort roles as well