Use :last-child selector for adjusting .card-header border

app/assets/stylesheets/framework/card.scss

 .card-header {
   &:first-child {
     // intended use case: card with only a header (for example empty related issues)
-    &.border-0,
-    &.border-bottom-0 {
+    &:last-child {
       @include border-radius($card-inner-border-radius);
     }
   }

changelogs/unreleased/winh-related-issues-border.yml

 ---
 title: Redo fix for related issues border radius
-merge_request: 17172
+merge_request: 17480
 author:
 type: fixed

ee/app/assets/javascripts/related_issues/components/related_issues_block.vue

@@ -217,10 +217,8 @@ export default {
         />
       </div>
       <div
-        :class="{
-          collapsed: !shouldShowTokenBody,
-          'sortable-container': canReorder,
-        }"
+        v-if="shouldShowTokenBody"
+        :class="{ 'sortable-container': canReorder }"
         class="related-issues-token-body"
       >
         <div v-if="isFetching" class="related-issues-loading-icon qa-related-issues-loading-icon">

ee/app/assets/stylesheets/pages/issues/related_issues.scss

@@ -19,17 +19,6 @@ $token-spacing-bottom: 0.5em;
 
 .related-issues-token-body {
   padding: 0;
-  transition-property: max-height, padding, opacity;
-  transition-duration: $general-hover-transition-duration;
-  transition-timing-function: $general-hover-transition-curve;
-
-  &.collapsed {
-    overflow: hidden;
-    max-height: 0;
-    padding-top: 0;
-    padding-bottom: 0;
-    opacity: 0;
-  }
 
   li .issuable-info-container {
     padding-left: $gl-padding;

ee/spec/javascripts/epic/components/epic_body_spec.js

@@ -58,7 +58,7 @@ describe('EpicBodyComponent', () => {
       expect(relatedEpicsEl.querySelector('.card-title').innerText.trim()).toContain('Epics');
       expect(relatedEpicsEl.querySelector('.js-related-issues-header-issue-count')).not.toBeNull();
       expect(relatedEpicsEl.querySelector('button.js-issue-count-badge-add-button')).not.toBeNull();
-      expect(relatedEpicsEl.querySelector('.related-items-list')).not.toBeNull();
+      expect(relatedEpicsEl.querySelector('.related-items-list')).toBeNull();
     });
 
     it('renders related issues list elements', () => {
@@ -71,7 +71,7 @@ describe('EpicBodyComponent', () => {
         relatedIssuesEl.querySelector('button.js-issue-count-badge-add-button'),
       ).not.toBeNull();
 
-      expect(relatedIssuesEl.querySelector('.related-items-list')).not.toBeNull();
+      expect(relatedIssuesEl.querySelector('.related-items-list')).toBeNull();
     });
   });
 });