fix: use showId instead of show slug to update playlist entries

refs #271

src/components/playlist/APlaylistEditor.vue

@@ -276,7 +276,7 @@ async function createPlaylist() {
 
 async function addFileToPlaylist(...files: TankFile[]) {
   await updatePlaylistEntries(
-    ...files.map((file) => ({ file: { id: file.id, show: props.show.slug } })),
+    ...files.map((file) => ({ file: { id: file.id, showId: props.show.id } })),
   )
 }