subgraph-availability-oracle image tag

[cjorge-graphops]

Upstream does not use versioning for SAO.

The chart has by default imagePullPolicy: ifNotAvailable, meaning it won't be updated (unless on a Node change or otherwise the image is missing locally).

We should change from using a tag to use digests for this chart to bring it in line with the lifecycle/release standard of the other charts. May also require some Renovate adjustments.

[calinah]

this is no longer relevant as SAO has implemented releases. Instead we'll add versions as per current renovate pattern #317