[SLO] Fix updating old SLO with non-revision bump

[kdelemme]

Summary

Incident: https://elastic.slack.com/archives/C087YQPEJ30

A change in the tags definitions of a few SLOs have been pushed which triggered an update without bump in the revision. This means only the ingest pipeline was updated to propagate the new tags to the summary documents.
Unfortunately, the SLO was on a previous version, and its summary transform was not generating specific fields that are expected by the latest ingest pipeline in order to compute some fields (the burn rate values).

When updating an SLO, we should check if the SLO is running on the latest version or not, and consider any changes as a breaking change if it is not on the latest version.
Updating the name when the SLO is on the latest version should not trigger a revision change, but updating the name when the SLO is on a previous version should trigger a revision change, and therefore a full reinstallation.

[elasticmachine]

Pinging @elastic/obs-ux-management-team (Team:obs-ux-management)