remove js-base64 dependency

package-lock.json

@@ -64,10 +64,7 @@
     "addons/addon-clipboard": {
       "name": "@xterm/addon-clipboard",
       "version": "0.2.0",
-      "license": "MIT",
-      "dependencies": {
-        "js-base64": "^3.7.5"
-      }
+      "license": "MIT"
     },
     "addons/addon-fit": {
       "name": "@xterm/addon-fit",
@@ -5420,11 +5417,6 @@
         "url": "https://github.com/chalk/supports-color?sponsor=1"
       }
     },
-    "node_modules/js-base64": {
-      "version": "3.7.8",
-      "resolved": "https://registry.npmjs.org/js-base64/-/js-base64-3.7.8.tgz",
-      "integrity": "sha512-hNngCeKxIUQiEUN3GPJOkz4wF/YvdUdbNL9hsBcMQTkKzboD7T/q3OYOuuPZLUE6dBxSGpwhk5mwuDud7JVAow=="
-    },
     "node_modules/js-tokens": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-4.0.0.tgz",