Apply FE reviewer suggestion

- Use data testid attribute for testing
issue weight count

- Use yaml as the source of truth for
FF default status

- Remove unused GlFeatureFlagMixin

app/assets/javascripts/boards/components/board_list_header.vue

@@ -328,6 +328,7 @@ export default {
 
       <div
         class="issue-count-badge gl-display-inline-flex gl-pr-0 no-drag gl-text-gray-500"
+        data-testid="issue-count-badge"
         :class="{
           'gl-display-none!': list.collapsed && isSwimlanesHeader,
           'gl-p-0': list.collapsed,

app/assets/javascripts/boards/components/board_new_issue.vue

@@ -4,7 +4,6 @@ import { mapActions, mapGetters, mapState } from 'vuex';
 import { getMilestone } from 'ee_else_ce/boards/boards_util';
 import BoardNewIssueMixin from 'ee_else_ce/boards/mixins/board_new_issue';
 import { __ } from '~/locale';
-import glFeatureFlagMixin from '~/vue_shared/mixins/gl_feature_flags_mixin';
 import eventHub from '../eventhub';
 import ProjectSelect from './project_select.vue';
 
@@ -18,7 +17,7 @@ export default {
     ProjectSelect,
     GlButton,
   },
-  mixins: [glFeatureFlagMixin(), BoardNewIssueMixin],
+  mixins: [BoardNewIssueMixin],
   inject: ['groupId'],
   props: {
     list: {

app/controllers/projects/boards_controller.rb

@@ -10,7 +10,7 @@ class Projects::BoardsController < Projects::ApplicationController
   before_action do
     push_frontend_feature_flag(:add_issues_button)
     push_frontend_feature_flag(:swimlanes_buffered_rendering, project, default_enabled: :yaml)
-    push_frontend_feature_flag(:graphql_board_lists, project, default_enabled: false)
+    push_frontend_feature_flag(:graphql_board_lists, project, default_enabled: :yaml)
   end
 
   feature_category :boards

ee/spec/features/boards/boards_spec.rb

@@ -345,7 +345,7 @@ RSpec.describe 'Project issue boards', :js do
   end
 
   def list_weight_badge(list)
-    find(".board[data-id='gid://gitlab/List/#{list.id}'] .issue-count-badge")
+    find(".board[data-id='gid://gitlab/List/#{list.id}'] [data-testid='issue-count-badge']")
   end
 
   def card_weight_badge(list)