[yaml] Fix YAML join with upstream ReadFromPubSub #30647

Job	Run time
Build python source distribution	1m 26s
Check environment variables	11s
Build python cp39- wheels on auto for ubuntu-20.04	20m 26s
Prepare GCS	0s
Build python cp310- wheels on auto for ubuntu-20.04	19m 1s
Build python cp311- wheels on auto for ubuntu-20.04	21m 24s
Build python cp312- wheels on auto for ubuntu-20.04	19m 1s
Build python cp39- wheels on auto for macos-13	19s
Build python cp310- wheels on auto for macos-13	17s
Build python cp311- wheels on auto for macos-13	28s
Build python cp312- wheels on auto for macos-13	3m 51s
Build python cp39- wheels on auto for windows-latest	16s
Build python cp310- wheels on auto for windows-latest	19s
Build python cp311- wheels on auto for windows-latest	17s
Build python cp312- wheels on auto for windows-latest	5m 9s
Upload python source distribution to GCS bucket	0s
Build python cp39- wheels on aarch64 for ubuntu-20.04	42s
Build python cp310- wheels on aarch64 for ubuntu-20.04	41s
Build python cp311- wheels on aarch64 for ubuntu-20.04	39s
Build python cp312- wheels on aarch64 for ubuntu-20.04	55m 34s
Upload wheels to GCS bucket	0s
Branch repo nightly	0s
List files on Google Cloud Storage Bucket	0s
	2h 30m 1s

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