Move ServerStarted telemetry after initialization

[conniey]

What does this PR do?

Moves ServerStarted telemetry until after host services have started. They were not being published to AppInsights before.

GitHub issue number?

Pre-merge Checklist

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[Copilot]

Pull Request Overview

This PR moves the ServerStarted telemetry emission to occur after the host services have started, ensuring that telemetry is properly published to AppInsights. Previously, the telemetry was being logged before the host was started, which prevented it from being sent.

• Reordered the host startup sequence to emit telemetry after host.StartAsync() completes
• Ensures telemetry service is fully initialized before logging startup metrics