enhance(admin): show impersonation banner and keep password change with the user (#38924)

Follow-up to https://github.com/go-gitea/gitea/pull/38614

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

web_src/css/modules/navbar.css

@@ -7,11 +7,6 @@
   padding: 0 10px;
 }
 
-/* When notification message is present after navbar, hide border to avoid double border */
-#navbar:has(+ .ui.message) {
-  border-bottom: none;
-}
-
 #navbar .navbar-left,
 #navbar .navbar-right {
   display: flex;