Internal server is broken

[rubenvp8510]

Describe the bug

Currently if I enable the internal server tempo crash with this log

goroutine 1 [running]:
flag.(*FlagSet).Var(0xc0001dc150, {0x2da4848, 0xc0006a65c8}, {0x275e37a, 0x9}, {0x2809a9f, 0x5c})
        /usr/local/go/src/flag/flag.go:1028 +0x3a5
github.com/grafana/dskit/log.(*Level).RegisterFlags(0xc0009bc4b8?, 0x1?)
        /home/rvargasp/redhat/tempo/vendor/github.com/grafana/dskit/log/level.go:37 +0x58
github.com/grafana/tempo/cmd/tempo/app.(*Config).RegisterFlagsAndApplyDefaults(0xc0006a6000, {0x0, 0x0}, 0x2765074?)
        /home/rvargasp/redhat/tempo/cmd/tempo/app/config.go:84 +0x37c
main.loadConfig()
        /home/rvargasp/redhat/tempo/cmd/tempo/main.go:176 +0x2b7
main.main()
        /home/rvargasp/redhat/tempo/cmd/tempo/main.go:63 +0xd2

To Reproduce
Steps to reproduce the behavior:

1. Start Tempo with internal server enabled

internal_server:
  enable: true

Expected behavior

Tempo should start as usual.

Environment:

• Infrastructure: [e.g., Kubernetes, bare-metal, laptop]
• Deployment tool: [e.g., helm, jsonnet]

Additional Context