chore: temp fix for failing unit teses in service management

[JoeWang1127]

In this PR:

• Ignore failing unit tests in service management.

This is a temporary fix of googleapis/sdk-platform-java#1839.

Confirm the change can generate @Ignore annotation to failing tests:

pip install library_generation
python library_generation/generate_repo.py generate --generation-config-yaml="$(pwd)"/generation_config.yaml --target-library-api-shortname=servicemanagement

For simplicity, I copied library_generation directory in sdk-platform-java to my local google-cloud-java repo.

[suztomo]

Thank you for writing the confirmation in the description.