[Misc] fix(dashboard): proxy Jaeger /dependencies route

[samzong]

Add missing Jaeger proxy routes for /dependencies page and /api/dependencies API. Previously these requests fell through to the static file server and returned HTML instead of proxying to Jaeger.

FIX #xxxx (link existing issues this PR will resolve)

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[github-actions]

👥 vLLM Semantic Team Notification

The following members have been identified for the changed files in this PR and have been automatically assigned:

📁 dashboard

Owners: @JaredforReal, @Xunzhuo
Files changed:

• dashboard/backend/router/router.go

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🎉 Thanks for your contributions!

This comment was automatically generated based on the OWNER files in the repository.

[JaredforReal]

@samzong Thanks!
/lgtm