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-multiple-subtitles/src/index.js

@@ -93,7 +93,3 @@ export default function artplayerPluginMultipleSubtitles({ subtitles = [] }) {
     }
   }
 }
-
-if (typeof window !== 'undefined') {
-  window.artplayerPluginMultipleSubtitles = artplayerPluginMultipleSubtitles
-}