Clone button enhancements (#33362) (#33404)

Backport #33362 by @silverwind

- Add box-shadow to default tippy theme
- Make colors for tabs match the ones from `.ui.tabular.menu`
- Remove tippy arrow and slightly offset tooltip closer to the button
- Fix setting of `aria-haspopup` when default role is used with tippy

<img width="335" alt="image"
src="https://github.com/user-attachments/assets/8633ebac-a43f-457a-86bd-7a88a83519ee"
/>

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

web_src/css/repo.css

@@ -1669,7 +1669,7 @@ td .commit-summary {
 }
 
 .repo-button-row-left {
-  flex: 1;
+  flex-grow: 1;
 }
 
 .repo-button-row .button {