fix: Seek not applied in play method (#1695)

# Description

This PR is fixing the bug in which in web while initialising the play
with duration specified, there was no seek happening, which means that
it starts from the beginning itself. setting the source before calling
seek in play() function, instead of setting it afterwards solves the
issue.

Closes #1597

packages/audioplayers/lib/src/audioplayer.dart

@@ -199,10 +199,12 @@ class AudioPlayer {
     if (ctx != null) {
       await setAudioContext(ctx);
     }
+
+    await setSource(source);
     if (position != null) {
       await seek(position);
     }
-    await setSource(source);
+
     await resume();
   }