kdenlive: Add system-observe plug
Kdenlive needs system-observe to communicate with its kdenlive_render process.
See https://forum.snapcraft.io/t/kdenlive-cannot-render-any-projects-stuck-in-waiting/26689/11
Kdenlive needs system-observe to communicate with its kdenlive_render process.
See https://forum.snapcraft.io/t/kdenlive-cannot-render-any-projects-stuck-in-waiting/26689/11