fix: update lyrics tooltip condition to handle null track safely

src/pages/Playroom.vue

@@ -656,7 +656,7 @@ watch(() => playQueueStore.currentIndex, () => {
 								</button>
 								<!-- Show tooltip only on hover, with transition -->
 								<transition name="lyrics-tooltip-fade">
-									<div v-if="showLyricsTooltip && getCurrentTrack() === null && !getCurrentTrack()!.song.lyricUrl"
+									<div v-if="showLyricsTooltip && !getCurrentTrack()?.song.lyricUrl"
 										class="absolute bottom-10 w-60 left-[-7rem] bg-black/60 backdrop-blur-3xl rounded-md p-2 text-xs flex flex-col text-left shadow-2xl border border-[#ffffff39]">
 										<div class="font-semibold text-white">这首曲目不提供歌词文本</div>
 										<div class="text-white/60">启用歌词时，将会在下一首有歌词的曲目中显示歌词文本。</div>