Update feature flags empty state

- Align buttons in the center
- Remove double top border

ee/app/views/projects/feature_flags/_empty_state.html.haml

-.border-top
-  .row.empty-state
+.row.empty-state
   .col-12
     .svg-content
       = image_tag 'illustrations/feature_flag.svg'
@@ -10,6 +9,6 @@
       %p
         = s_('FeatureFlags|Feature flags allow you to configure your code into different flavors by dynamically toggling certain functionality.')
         = link_to 'More information', help_page_path("user/project/operations/feature_flags")
-
+      .text-center
         = render 'new_feature_flag_button'
         = render 'configure_feature_flags_button'

ee/changelogs/unreleased/gt-update-feature-flags-empty-state.yml

+---
+title: Update feature flags empty state
+merge_request: 7967
+author: George Tsiolis
+type: other