chore: Remove live update for study group dashboard

Live updates have been disabled for 5 years.

Related to #b2fc574

Author: arkirchner

app/assets/javascripts/channels/la_exercises.js

@@ -3,14 +3,12 @@
 class Comment < ApplicationRecord
   # inherit the creation module: encapsulates that this is a polymorphic user, offers some aliases and makes sure that all necessary attributes are set.
   include Creation
-  include ActionCableHelper
 
   attr_accessor :username, :date, :updated, :editable
 
   belongs_to :file, class_name: 'CodeOcean::File'
   has_one :submission, through: :file, source: :context, source_type: 'Submission'
   has_one :request_for_comment, through: :submission
-  # after_save :trigger_rfc_action_cable_from_comment
 
   def only_comment_for_rfc?
     request_for_comment.comments.one?

app/channels/la_exercises_channel.rb

@@ -2,7 +2,6 @@
 
 class RequestForComment < ApplicationRecord
   include Creation
-  include ActionCableHelper
 
   # SOLVED:      The author explicitly marked the RfC as solved.
   # SOFT_SOLVED: The author did not mark the RfC as solved but reached the maximum score in the corresponding exercise at any time.
@@ -21,8 +20,6 @@ class RequestForComment < ApplicationRecord
   scope :in_range, ->(from, to) { from == DateTime.new(0) && to > 5.seconds.ago ? all : where(created_at: from..to) }
   scope :with_comments, -> { select {|rfc| rfc.comments.any? } }
 
-  # after_save :trigger_rfc_action_cable
-
   def commenters
     comments.map(&:user).uniq
   end

app/helpers/action_cable_helper.rb

@@ -3,7 +3,6 @@
 class Submission < ApplicationRecord
   include Context
   include ContributorCreation
-  include ActionCableHelper
 
   CAUSES = %w[assess download file render run save submit test autosave requestComments remoteAssess
               remoteSubmit].freeze
@@ -48,8 +47,6 @@ class Submission < ApplicationRecord
 
   validates :cause, inclusion: {in: CAUSES}
 
-  # after_save :trigger_working_times_action_cable
-
   def collect_files
     @collect_files ||= begin
       ancestors = build_files_hash(exercise&.files&.includes(:file_type), :id)