TF-1684 Remove library not used

(cherry picked from commit 9873eeac72a368e9ae91baf366507e54b6a4ed5e)

pubspec.lock

@@ -870,14 +870,6 @@ packages:
       url: "https://github.com/linagora/html-editor-enhanced.git"
     source: git
     version: "2.5.1"
-  html_unescape:
-    dependency: "direct main"
-    description:
-      name: html_unescape
-      sha256: "15362d7a18f19d7b742ef8dcb811f5fd2a2df98db9f80ea393c075189e0b61e3"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.0.0"
   http:
     dependency: transitive
     description:

pubspec.yaml

@@ -176,8 +176,6 @@ dependencies:
 
   flutter_local_notifications: 13.0.0
 
-  html_unescape: 2.0.0
-
   fading_edge_scrollview: 3.0.0
 
   focused_menu_custom: 1.2.0