Fix rounded border for segment followed by pagination (#30809) (#30818)

Backport #30809 by @silverwind

Fixes https://github.com/go-gitea/gitea/issues/30673, specifically
https://github.com/go-gitea/gitea/issues/30673#issuecomment-2085329812.

Co-authored-by: silverwind <me@silverwind.io>

web_src/css/modules/segment.css

@@ -152,6 +152,7 @@
 }
 
 .ui.attached.segment:has(+ .ui[class*="top attached"].header),
+.ui.attached.segment:has(+ .page.buttons),
 .ui.attached.segment:last-child,
 .ui.segment:has(+ .ui.segment:not(.attached)),
 .ui.attached.segment:has(+ .ui.modal) {