refactor: remove global window assignment for Artplayer and template export

- Removed the assignment of Artplayer to the global window object in index.js of the artplayer package.
- Eliminated the window export for the template plugin in index.js, streamlining the code and reducing global scope pollution.

packages/artplayer-plugin-document-pip/src/index.js

@@ -193,10 +193,6 @@ export default function artplayerPluginDocumentPip(userOptions = {}) {
   }
 }
 
-if (typeof window !== 'undefined') {
-  window.artplayerPluginDocumentPip = artplayerPluginDocumentPip
-}
-
 if (typeof document !== 'undefined') {
   const id = 'artplayer-plugin-document-pip'
   let $style = document.getElementById(id)