fix https://github.com/openimsdk/open-im-server/issues/2895

[morya]

🅰 Please add the issue ID after "Fixes #"

Fixes #2895

[skiffer-git]

[2024-11-26 09:10:25 UTC] Some programs are not running properly:
binary openim-msggateway is not running as expected: /home/runner/work/open-im-server/open-im-server/_output/bin/platforms/linux/amd64/openim-msggateway expected 1 processes, but 0 running

[morya]

[2024-11-26 09:10:25 UTC] Some programs are not running properly: binary openim-msggateway is not running as expected: /home/runner/work/open-im-server/open-im-server/_output/bin/platforms/linux/amd64/openim-msggateway expected 1 processes, but 0 running

when there are no rpc.ports config inside './config/openim-msggateway.yml' , code will fail to run due to index error.

last commit fix it.

[morya]

conflict has been resolved