Removed unused ApplicationController#set_filter_values method

The instance variables assigned in `set_filter_values` are not used by
anything anymore.

app/controllers/application_controller.rb

@@ -286,40 +286,15 @@ class ApplicationController < ActionController::Base
     @filter_params
   end
 
-  def set_filter_values(collection)
-    assignee_id = @filter_params[:assignee_id]
-    author_id = @filter_params[:author_id]
-    milestone_id = @filter_params[:milestone_id]
-
-    @sort = @filter_params[:sort]
-    @assignees = User.where(id: collection.pluck(:assignee_id))
-    @authors = User.where(id: collection.pluck(:author_id))
-    @milestones = Milestone.where(id: collection.pluck(:milestone_id))
-
-    if assignee_id.present? && !assignee_id.to_i.zero?
-      @assignee = @assignees.find_by(id: assignee_id)
-    end
-
-    if author_id.present? && !author_id.to_i.zero?
-      @author = @authors.find_by(id: author_id)
-    end
-
-    if milestone_id.present? && !milestone_id.to_i.zero?
-      @milestone = @milestones.find_by(id: milestone_id)
-    end
-  end
-
   def get_issues_collection
     set_filters_params
     issues = IssuesFinder.new.execute(current_user, @filter_params)
-    set_filter_values(issues)
     issues
   end
 
   def get_merge_requests_collection
     set_filters_params
     merge_requests = MergeRequestsFinder.new.execute(current_user, @filter_params)
-    set_filter_values(merge_requests)
     merge_requests
   end