Upgrade setuptools and ProtoBuf Python in prep_xds.sh (#26029)

* Upgrade

* Trick Kokoro to run xDS test

* Restore grpc_python_bazel_test.cfg

* Update protobuf

* Add extra layer of protection

tools/run_tests/helper_scripts/prep_xds.sh

@@ -20,7 +20,8 @@ cd "$(dirname "$0")/../../.."
 
 sudo apt-get install -y python3-pip
 sudo python3 -m pip install --upgrade pip
-sudo python3 -m pip install grpcio==1.31.0 grpcio-tools==1.31.0 google-api-python-client google-auth-httplib2 oauth2client xds-protos
+sudo python3 -m pip install --upgrade setuptools
+sudo python3 -m pip install --upgrade grpcio==1.31.0 grpcio-tools==1.31.0 protobuf google-api-python-client google-auth-httplib2 oauth2client xds-protos
 
 # Prepare generated Python code.
 TOOLS_DIR=tools/run_tests

tools/run_tests/run_xds_tests.py

@@ -44,12 +44,17 @@ from src.proto.grpc.testing import test_pb2_grpc
 
 # Envoy protos provided by PyPI package xds-protos
 # Needs to import the generated Python file to load descriptors
+try:
     from envoy.service.status.v3 import csds_pb2
     from envoy.service.status.v3 import csds_pb2_grpc
     from envoy.extensions.filters.network.http_connection_manager.v3 import http_connection_manager_pb2
     from envoy.extensions.filters.common.fault.v3 import fault_pb2
     from envoy.extensions.filters.http.fault.v3 import fault_pb2
     from envoy.extensions.filters.http.router.v3 import router_pb2
+except ImportError:
+    # These protos are required by CSDS test. We should not fail the entire
+    # script for one test case.
+    pass
 
 logger = logging.getLogger()
 console_handler = logging.StreamHandler()