fix: ChainType choices (to support consumer chains)

[bap2pecs]

Summary

fix a small bug which was introduced in #155

this caused FP failed to start

bash-5.1$ fpd start
service injective.evm.v1beta1.Msg does not have cosmos.msg.v1.service proto annotation
Error: failed to load configuration: /home/finality-provider/.fpd/fpd.conf:6: Invalid value `OPStackL2' for option `--chaintype'. Allowed values are: 
Usage:
  fpd start [flags]

Test Plan

tested with a new docker image created by CI

babylonlabs/finality-provider:9fcbde4fdacd26de256a944dedacb645826c2e9e

and it doesn't have this error anymore

[bap2pecs]

this one still seems flaky. rerunning.