Add end-of-support date to available updates (#39732)

app/javascript/styles/mastodon/tables.scss

@@ -15,10 +15,14 @@
     text-align: start;
     background: var(--color-bg-primary);
 
-    &.critical {
+    .critical {
       font-weight: 700;
       color: var(--color-text-warning);
     }
+
+    .unsupported {
+      color: var(--color-text-error);
+    }
   }
 
   .align-end {