Remove externs for deleted API musicManagerPrivate

PiperOrigin-RevId: 501425967

Author: Closure Team

contrib/externs/chrome_extensions.js

@@ -11004,19 +11004,6 @@ chrome.serial.onReceiveError;
 ////////////////////////////////////////////////////////////////////////////////
 
 
-/**
- * @const
- */
-chrome.musicManagerPrivate = {};
-
-
-/**
- * @param {function(string): void} callback
- * @return {undefined}
- */
-chrome.musicManagerPrivate.getDeviceId = function(callback) {};
-
-
 /**
  * @const
  */