FIX: remove unsuppored rake task

rebuilding user_actions is not something that should be done.

Plugins such as solved and assigned extend it, there are tons of
little rules that were not captured in `user_actions:rebuild`

lib/tasks/user_actions.rake

@@ -1,41 +0,0 @@
-# frozen_string_literal: true
-
-desc "rebuild the user_actions table"
-task "user_actions:rebuild" => :environment do
-  MessageBus.off
-  UserAction.delete_all
-  PostAction.all.each do |i|
-    if i.deleted_at.nil?
-      UserActionManager.post_action_created(i)
-    else
-      UserActionManager.post_action_destroyed(i)
-    end
-  end
-  Topic.all.each { |i| UserActionManager.log_topic(i) }
-  Post.all.each do |i|
-    if i.deleted_at.nil?
-      UserActionManager.post_created(i)
-    else
-      UserActionManager.post_destroyed(i)
-    end
-  end
-  Notification.all.each do |notification|
-
-    if notification.post.deleted_at.nil?
-      UserActionManager.notification_created(
-        notification.post,
-        notification.user,
-        notification.notification_type,
-        notification.user
-      )
-    else
-      UserActionManager.notification_destroyed(
-        notification.post,
-        notification.user,
-        notification.notification_type,
-        notification.user
-      )
-    end
-
-  end
-end