Add server schema for microversion 2.57

This commit adds servers schema for microversion 2.57
Without those schema in this file, get_schema() method
will throw error about particular schema not found in this file.

Change-Id: Ib5a9886bff2f0c7d8ba5be413703cf2eb39fc9d1
partially-implements: blueprint full-schema-for-all-microversions
diff --git a/tempest/lib/api_schema/response/compute/v2_57/servers.py b/tempest/lib/api_schema/response/compute/v2_57/servers.py
index d7de5fd..0099a2b 100644
--- a/tempest/lib/api_schema/response/compute/v2_57/servers.py
+++ b/tempest/lib/api_schema/response/compute/v2_57/servers.py
@@ -50,8 +50,9 @@
 get_server = copy.deepcopy(servers254.get_server)
 list_servers_detail = copy.deepcopy(servers254.list_servers_detail)
 update_server = copy.deepcopy(servers254.update_server)
-
-# ****** Schemas unchanged since microversion 2.26 ***
+list_servers = copy.deepcopy(servers254.list_servers)
+show_server_diagnostics = copy.deepcopy(servers254.show_server_diagnostics)
+get_remote_consoles = copy.deepcopy(servers254.get_remote_consoles)
 list_tags = copy.deepcopy(servers254.list_tags)
 update_all_tags = copy.deepcopy(servers254.update_all_tags)
 delete_all_tags = copy.deepcopy(servers254.delete_all_tags)