Sync alert status to incident status on alert status updates

What does this MR do and why?

• Related issues: #330283 (closed), #332065 (closed)
• Dependent on: !76819 (merged), !76986 (merged)

This MR:

• Links the status between AlertManagement::Alerts & IncidentManagement::IssuableEscalationStatuses so that updates to one will update the other

Changelog is excluded, as feature is behind a feature flag.

Proposed flow for sync

How to set up and validate locally

1. See !76819 (merged) for preliminary setup
2. Compare results of running the issue update & the alert update:

   ::Issues::UpdateService.new(
     project: project, 
     current_user: user, 
     params: { escalation_status: { status: :resolved } }
   ).execute(incident)
   
   incident.escalation_status.reload.status
   incident.alert_management_alert.reload.status

   ::AlertManagement::Alerts::UpdateService.new(
     incident.alert_management_alert, 
     user, 
     { status: :triggered }
   ).execute(incident)
   
   incident.escalation_status.reload.status
   incident.alert_management_alert.reload.status

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.