musikr: compute uid on presong creation

musikr/src/main/java/org/oxycblt/musikr/graph/MusicGraph.kt

@@ -55,7 +55,7 @@ private class MusicGraphBuilderImpl : MusicGraph.Builder {
     private val playlistVertices = mutableSetOf<PlaylistVertex>()
 
     override fun add(preSong: PreSong) {
-        val uid = preSong.computeUid()
+        val uid = preSong.uid
         if (songVertices.containsKey(uid)) {
             return
         }

musikr/src/main/java/org/oxycblt/musikr/model/SongImpl.kt

@@ -42,7 +42,7 @@ internal interface SongCore {
 internal class SongImpl(private val handle: SongCore) : Song {
     private val preSong = handle.preSong
 
-    override val uid = preSong.computeUid()
+    override val uid = preSong.uid
     override val name = preSong.name
     override val track = preSong.track
     override val disc = preSong.disc

musikr/src/main/java/org/oxycblt/musikr/tag/interpret/PreMusic.kt

@@ -53,8 +53,7 @@ internal data class PreSong(
     val preArtists: List<PreArtist>,
     val preGenres: List<PreGenre>
 ) {
-    fun computeUid() =
-        musicBrainzId?.let { Music.UID.musicBrainz(Music.UID.Item.SONG, it) }
+    val uid = musicBrainzId?.let { Music.UID.musicBrainz(Music.UID.Item.SONG, it) }
         ?: Music.UID.auxio(Music.UID.Item.SONG) {
             // Song UIDs are based on the raw data without parsing so that they remain
             // consistent across music setting changes. Parents are not held up to the