Apply automatic rubocop fixes

app/channels/application_cable/channel.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ApplicationCable
   class Channel < ActionCable::Channel::Base
   end

app/channels/application_cable/connection.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ApplicationCable
   class Connection < ActionCable::Connection::Base
     identified_by :current_user
@@ -20,11 +22,7 @@ module ApplicationCable
     def find_verified_user
       # Finding the current_user is similar to the code used in application_controller.rb#current_user
       current_user = ExternalUser.find_by(id: session[:external_user_id]) || InternalUser.find_by(id: session[:user_id])
-      if current_user
-        current_user
-      else
-        reject_unauthorized_connection
-      end
+      current_user || reject_unauthorized_connection
     end
   end
 end

app/channels/la_exercises_channel.rb

@@ -1,5 +1,6 @@
-class LaExercisesChannel < ApplicationCable::Channel
+# frozen_string_literal: true
 
+class LaExercisesChannel < ApplicationCable::Channel
   def subscribed
     stream_from specific_channel
   end
@@ -9,6 +10,7 @@ class LaExercisesChannel < ApplicationCable::Channel
   end
 
   private
+
   def specific_channel
     reject unless StudyGroupPolicy.new(current_user, StudyGroup.find_by(id: params[:study_group_id])).stream_la?
     "la_exercises_#{params[:exercise_id]}_channel_study_group_#{params[:study_group_id]}"