flake: `TestWorkspaceProxyDERPMeshProbe/HealthyZero`

[ethanndickson]

     t.go:106: 2025-01-28 10:31:18.329 [debu]  net.derpmesh.client: WatchConnectionChanges: derphttp.Client.WatchConnectionChanges connect to http://127.0.0.1:62283/derp: GET failed: <nil>:  server_url=http://localhost:62248
    wsproxy_test.go:878: 
        	Error Trace:	/Users/runner/work/coder/coder/enterprise/wsproxy/wsproxy_test.go:878
        	Error:      	"[]" should have 1 item(s), but has 0
        	Test:       	TestWorkspaceProxyDERPMeshProbe/HealthyZero
        	Messages:   	proxy is healthy

https://github.com/coder/coder/actions/runs/13008398168/job/36280372686