Remove unused .issue-box CSS

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

app/assets/stylesheets/framework/variables.scss

@@ -468,7 +468,6 @@ $gl-line-height-20: 20px;
 $gl-line-height-24: 24px;
 $gl-line-height-14: 14px;
 
-$issue-box-upcoming-bg: #8f8f8f;
 $pages-group-name-color: #4c4e54;
 
 /*

app/assets/stylesheets/pages/issuable.scss

@@ -693,10 +693,6 @@
 
 .issuable-list {
   li {
-    .issue-box {
-      display: flex;
-    }
-
     .issuable-info-container {
       flex: 1;
       display: flex;

changelogs/unreleased/284602-remove-issue-box-css.yml

+---
+title: Remove unused .issue-box CSS
+merge_request: 48002
+author: Takuya Noguchi
+type: other