2025-05: missing update to systemlink values yaml

[dash042]

breaking change described in the 2025-05 release:

1. Set the `ingestion.streamPool.bufferSize` value to the product of the old
   `ingestion.s3StreamPool.blocksPerBuffer` and
   values were `blocksPerBuffer=3` and `blockSize=5MiB`, so the new default
   value is `bufferSize=15MiB`.

Unable to find previous blockSize values in install-systemlink-enterprise repository:

org:ni blocksPerBuffer --> only finds 2025-05 Release notes readme.md

So there e.g. never seems to have been a e.g. "blocksPerBuffer" value in the default value yaml.

[spanglerco]

ingestion.streamPool.bufferSize doesn't need to be set if neither ingestion.s3StreamPool.blocksPerBuffer nor ingestion.s3StreamPool.blockSize were being set previously.

@prestwick if it's possible, we may want to consider editing the 2025-05 release notes to clarify this. I also just put up #269 to fix the template systemlink-values.yaml related to this issue.