Clone panel fixes (#15435)

- Use <button> over <div> for a button
- Fix absent border-right on wiki
- Fix absent border-radius on wiki

Co-authored-by: 6543 <6543@obermui.de>

web_src/less/_repository.less

@@ -201,18 +201,25 @@
     .clone.button {
       font-size: 13px;
       padding: 7.5px 5px;
-
-      &:first-child {
-        border-radius: var(--border-radius) 0 0 var(--border-radius);
-      }
     }
 
     #repo-clone-https,
-    #repo-clone-ssh,
-    #clipboard-btn {
+    #repo-clone-ssh {
       border-right: none;
     }
 
+    #download-btn {
+      border-left: none;
+    }
+
+    button:first-of-type {
+      border-radius: var(--border-radius) 0 0 var(--border-radius) !important;
+    }
+
+    button:last-of-type {
+      border-radius: 0 var(--border-radius) var(--border-radius) 0 !important;
+    }
+
     .icon.button {
       padding: 0 10px;
     }