[bazel rbe] RBE config: update names of some deprecated bazel option flags (#33759)

just a bit of cleanup

tools/remote_build/include/rbe_base_config.bazelrc

@@ -27,8 +27,7 @@ build --remote_instance_name=projects/grpc-testing/instances/default_instance
 # unless overridden by --google_credentials=service_account_credentials.json
 # How to setup credentials to be able to use bazel RBE locally:
 # https://cloud.google.com/remote-build-execution/docs/results-ui/getting-started-results-ui
-# TODO(jtattermusch): Option 'auth_enabled' is deprecated: Use --google_default_credentials instead
-build --auth_enabled=true
+build --google_default_credentials
 
 # use remote cache (remote execution needs to be configured separately)
 # Note that remote cache is needed
@@ -41,5 +40,4 @@ build --remote_cache=grpcs://remotebuildexecution.googleapis.com
 build --bes_backend=grpcs://buildeventservice.googleapis.com
 build --bes_timeout=600s
 build --bes_results_url="https://source.cloud.google.com/results/invocations/"
-# TODO(jtattermusch): Option 'project_id' is deprecated: Use --bes_instance_name instead
-build --project_id=grpc-testing
+build --bes_instance_name=grpc-testing

tools/remote_build/include/rbe_remote_execution.bazelrc

@@ -30,8 +30,7 @@ build --remote_timeout=7200  # very large value to avoid problems like https://g
 # and port server won't be available.
 build --define GRPC_PORT_ISOLATED_RUNTIME=1
 
-# TODO(jtattermusch): is this still required for remote execution to work?
-# TODO(jtattermusch): Option 'experimental_strict_action_env' is deprecated: Use --incompatible_strict_action_env instead
-build --experimental_strict_action_env=true
+# Prevents host environment variables from leaking into Bazel actions and ensures that the remote cache is shared across machines
+build --incompatible_strict_action_env=true
 # TODO(jtattermusch): is this still required for remote execution to work?
 build --action_env=BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1