make search box in issue sidebar dropdown list always show when scrolling (#32576)

as title, replace #31597 after #32460 

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Signed-off-by: a1012112796 <1012112796@qq.com>

web_src/css/repo.css

@@ -66,6 +66,12 @@
   overflow-x: auto;
 }
 
+.issue-content-right .dropdown > .menu .item-secondary-info small {
+  display: block;
+  text-overflow: ellipsis;
+  overflow: hidden;
+}
+
 @media (max-width: 767.98px) {
   .issue-content-left,
   .issue-content-right {