stage workers should not connect to production rabbitmq

[Sancus]

https://github.com/thunderbird/addons-server/blob/stage/infra/pulumi/config.stage.yaml#L143

[e9e4e5f0faef]

Follow-up isolation audit status

Completed a broader audit of the stage service configuration and an additional result-backend misconfiguration was corrected so that it now points to the intended stage Redis target.

Current status:

• database settings verified as stage-scoped
• cache settings verified as stage-scoped
• search remains shared by design
• result backend corrected and verified as stage-scoped
• broker remains the only unresolved environment-isolation blocker

The worker remains disabled with autoscaling suspended until the broker points to a stage-only target and that isolation is verified from the running stage task definition.