Remove artplayer-plugin-liquid-glass plugin

- Deleted the plugin files including JavaScript, CSS, README, and type definitions.
- Removed references to the plugin from the documentation.
- Cleaned up the package structure by removing the .npmignore and package.json files related to the plugin.

docs/index.html

@@ -112,10 +112,6 @@
                         <li>
                             <a href="/?libs=./uncompiled/artplayer-plugin-document-pip/index.js&example=document.pip">artplayer-plugin-document-pip</a>
                         </li>
-                        <li>
-                            <a
-                                href="/?libs=./uncompiled/artplayer-plugin-liquid-glass/index.js&example=liquid.glass">artplayer-plugin-liquid-glass</a>
-                        </li>
                         <li>
                             <a
                             href="/?libs=./uncompiled/artplayer-plugin-jassub/index.js&example=jassub">artplayer-plugin-jassub</a>