As the first step in credential consolidation, we replace
injection of application default credential in for KMS and
Drive.
Tests:
- for Drive, tested with exportDomainLists and exportReservedTerms.
- For KMS, used CLI commands (get_keyring_secret and update_kms_keyring) to change and
restore secret for one key.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=211819859
