fix: player volume bug (#1918)

* fix: player volume bug

* Update Player.js

* Update Player.js

* Update Player.js

* Update Player.js

Author: Nep-Timeline

src/utils/Player.js

@@ -146,7 +146,7 @@ export default class {
   }
   set volume(volume) {
     this._volume = volume;
-    Howler.volume(volume);
+    this._howler?.volume(volume)
   }
   get list() {
     return this.shuffle ? this._shuffledList : this._list;
@@ -207,7 +207,7 @@ export default class {
 
   _init() {
     this._loadSelfFromLocalStorage();
-    Howler.volume(this.volume);
+    this._howler?.volume(this.volume);
 
     if (this._enabled) {
       // 恢复当前播放歌曲