Migrate Start Review button on MRs to use confirm variant

app/assets/javascripts/notes/components/note_form.vue

@@ -390,7 +390,7 @@ export default {
             <gl-button
               :disabled="isDisabled"
               category="primary"
-              variant="success"
+              variant="confirm"
               class="gl-mr-3"
               data-qa-selector="start_review_button"
               @click="handleAddToReview"

changelogs/unreleased/mr-thread-comment-button.yml

+---
+title: Migrate Start Review button on MRs to use confirm variant
+merge_request: 59523
+author:
+type: changed