Remove slack slash commands `run` double up

ee/changelogs/unreleased/slash_commands_double_run.yml

+---
+title: Remove slack slash commands double up
+merge_request: 10555
+author:
+type: fixed

ee/lib/ee/gitlab/slash_commands/command.rb

-# frozen_string_literal: true
-
-module EE
-  module Gitlab
-    module SlashCommands
-      module Command
-        extend ActiveSupport::Concern
-
-        class_methods do
-          extend ::Gitlab::Utils::Override
-          override :commands
-
-          def commands
-            super.concat(
-              [
-                ::Gitlab::SlashCommands::Run
-              ]
-            )
-          end
-        end
-      end
-    end
-  end
-end

lib/gitlab/slash_commands/command.rb

@@ -3,8 +3,6 @@
 module Gitlab
   module SlashCommands
     class Command < BaseCommand
-      prepend EE::Gitlab::SlashCommands::Command # rubocop: disable Cop/InjectEnterpriseEditionModule
-
       def self.commands
         [
           Gitlab::SlashCommands::IssueShow,