[dashboard] Empty root-path causes redirect loop

[thejoeejoee]

Checklist:

• I've included steps to reproduce the bug.
• I've included the version of argo rollouts.

Describe the bug

When used dashboard on the plain non-prefixed URL (e.g. --root-path "" or --root-path "/"), dashboard server jumps into redirect loop.

To Reproduce

• run kubectl argo rollouts dashboard --root-path "/"
• enter http://localhost:3100

Expected behavior

Server should not return HTTP 302 with Location: / and just return the index.html of Dashboard.

Version

❯ kubectl argo rollouts version
kubectl-argo-rollouts: v1.7.2+59e5bd3
  BuildDate: 2024-08-13T18:29:47Z
  GitCommit: 59e5bd385c031600f86075beb9d77620f8d7915e
  GitTreeState: clean
  GoVersion: go1.21.13
  Compiler: gc
  Platform: darwin/amd64

Logs

❯ kubectl argo rollouts dashboard --root-path ""
INFO[0000] Argo Rollouts Dashboard is now available at http://localhost:3100/

❯ curl -iL http://localhost:3100/

...

HTTP/1.1 302 Found
Content-Type: text/html; charset=utf-8
Location: /
Date: Sat, 30 Nov 2024 13:44:45 GMT
Content-Length: 24

curl: (47) Maximum (50) redirects followed

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