sd-dhcp-server: do not assign address reserved for static leases to non-matching clients

This fix the root cause of the issue #22253.

src/libsystemd-network/sd-dhcp-server.c

@@ -801,6 +801,9 @@ static bool address_is_in_pool(sd_dhcp_server *server, be32_t address) {
             be32toh(address) >= (be32toh(server->subnet) | (server->pool_offset + server->pool_size)))
                 return false;
 
+        if (hashmap_contains(server->static_leases_by_address, UINT32_TO_PTR(address)))
+                return false;
+
         return true;
 }