Remove sortablejs which is unused

Author: tdonohue

package-lock.json

@@ -163,7 +163,6 @@
     "reflect-metadata": "^0.2.2",
     "rxjs": "^7.8.0",
     "sanitize-html": "^2.12.1",
-    "sortablejs": "1.15.0",
     "uuid": "^8.3.2",
     "webfontloader": "1.6.28",
     "zone.js": "~0.14.4"