rfac: handle paused scaling directly in reconciler

[rickbrouwer]

The ScaledObject reconciler now handles the full pause lifecycle: stop scale loop, delete HPA, and scale the target directly via the scale subresource instead of recreating an HPA with min=max=N. This applies consistently to both paused and paused-replicas annotations.

Also aligned the ScaledJob pause flow with the same status-first pattern and idempotent scale loop stopping.
Added e2e tests for HPA absence during pause, annotation value changes and annotation switching while paused.

Checklist

• I have verified that my change is according to the deprecations & breaking changes policy
• Tests have been added (if applicable)
• Ensure make generate-scalers-schema has been run to update any outdated generated files
• Changelog has been updated and is aligned with our changelog requirements, only when the change impacts end users
• Commits are signed with Developer Certificate of Origin (DCO - learn more)

Fixes #7663

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[rickbrouwer]

/run-e2e internal
Update: You can check the progress here

[rickbrouwer]

/run-e2e internal
Update: You can check the progress here

[rickbrouwer]

/run-e2e internal
Update: You can check the progress here