Fix (mostly) notifications on no-sidebar layout

This is still somewhat broken on very narrow screens if they have both
comment and message notifications, but that should be pretty uncommon.

tildes/scss/_layout.scss

@@ -47,7 +47,7 @@ body {
   }
 
   #site-header .logged-in-user-info {
-    display: block;
+    display: flex;
   }
 }
 

tildes/scss/modules/_logged-in-user.scss

@@ -18,8 +18,4 @@
 .logged-in-user-alert {
   font-weight: bold;
   font-size: 0.5rem;
-
-  @media (min-width: $size-md) {
-    margin-right: 1rem;
-  }
 }

tildes/scss/modules/_site-header.scss

@@ -2,6 +2,10 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
 #site-header {
+  .logged-in-user-alert {
+    margin-right: 1rem;
+  }
+
   .logged-in-user-info {
     // hidden on small screens
     display: none;