Give SyTest an exemption from Synapse room creation rate limiting

Tracks element-hq/synapse#18514

Author: reivilibre

lib/SyTest/Homeserver/Synapse.pm

@@ -241,6 +241,11 @@ sub start
             burst_count => 1000,
         },
 
+        rc_room_creation => {
+            per_second => 1000,
+            burst_count => 1000,
+        },
+
         enable_registration => "true",
         enable_registration_without_verification => "true",
         databases => \%db_configs,