[Bug] nil deref during TestServer_StartDev_ConcurrentStarts test

[josh-berry]

Running server start-dev multiple times concurrently may occasionally cause a nil dereference to occur.

This was caught by CI. Example run: https://github.com/temporalio/cli/actions/runs/10855312160/job/30127644431?pr=658

Backtrace:

     commands_test.go:182: Calling: server start-dev -p 60743 --headless --log-level never
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x20 pc=0xbaa90a]

goroutine 84720 [running]:
google.golang.org/grpc.(*Server).Serve(0xc002cae800, {0x0, 0x0})
	C:/Users/runneradmin/go/pkg/mod/google.golang.org/[email protected]/server.go:864 +0x16a
go.temporal.io/server/service/matching.(*Service).Start.func1()
	C:/Users/runneradmin/go/pkg/mod/go.temporal.io/[email protected]/service/matching/service.go:103 +0x65
created by go.temporal.io/server/service/matching.(*Service).Start in goroutine 84691
	C:/Users/runneradmin/go/pkg/mod/go.temporal.io/[email protected]/service/matching/service.go:101 +0x169