[Actionable Observability] Remove space awareness for SLO common resources

[kdelemme]

📝 Summary

Part of #137323

As mentioned by @maryam-saeidi in this comment and reason explained here, we should remove the {space} awareness from the common resources installed when creating an SLO.

Namely, we should have only one destination index used by all SLO created from any spaces. The SLO stored as KIbana Saved Objects are space aware, so we should not need to specify the space in the rollup data (transform parameters) for the time being. But we might have the need later.

✅ Acceptance Criteria

• Create an SLO from default space and from "other" space results in one destination index written into.

[elasticmachine]

Pinging @elastic/actionable-observability (Team: Actionable Observability)