[Glitch] Fix unread indicator on announcements not being aligned with text in web UI

Port 90f04ea064 to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/styles/components/announcements.scss

@@ -84,14 +84,13 @@
 
     &__unread {
       position: absolute;
-      top: 15px;
+      top: 19px;
-      right: 15px;
+      right: 19px;
-      display: inline-block;
+      display: block;
       background: $highlight-text-color;
       border-radius: 50%;
       width: 0.625rem;
       height: 0.625rem;
-      margin: 0 .15em;
     }
   }