libkmpris: test current player is set
Consolidates 9c5726ab
See also https://invent.kde.org/plasma/plasma-workspace/-/pipelines/480397 when 9c5726ab is reverted
Edited by Fushan Wen
Consolidates 9c5726ab
See also https://invent.kde.org/plasma/plasma-workspace/-/pipelines/480397 when 9c5726ab is reverted