Revise message to use 'after' not 'once'

This message needed refinement. Proper grammar, please and thank you!

app/assets/javascripts/vue_merge_request_widget/components/states/merge_checks_failed.vue

@@ -6,7 +6,7 @@ export default {
   i18n: {
     approvalNeeded: s__('mrWidget|Merge blocked: this merge request must be approved.'),
     blockingMergeRequests: s__(
-      'mrWidget|Merge blocked: you can only merge once above items are resolved.',
+      'mrWidget|Merge blocked: you can only merge after the above items are resolved.',
     ),
   },
   components: {

locale/gitlab.pot

@@ -42705,7 +42705,7 @@ msgstr ""
 msgid "mrWidget|Merge blocked: this merge request must be approved."
 msgstr ""
 
-msgid "mrWidget|Merge blocked: you can only merge once above items are resolved."
+msgid "mrWidget|Merge blocked: you can only merge after the above items are resolved."
 msgstr ""
 
 msgid "mrWidget|Merge failed."