Replace outdated css attribute (#9912)

Author: justjanne

res/css/views/rooms/_EventTile.pcss

@@ -1309,7 +1309,7 @@ $left-gutter: 64px;
 
 .mx_EventTile_details {
     display: flex;
-    width: fill-available;
+    width: stretch;
     align-items: center;
     justify-content: space-between;
     gap: $spacing-8;