feat: allow to check new subgraphs

[JivusAyrus]

Motivation and Context

This PR allows to run a check with a new subgraph. The user will have to specify the labels of the new subgraph using the --label option in the subgraph check command.

Checklist

• [x] I have discussed my proposed changes in an issue and have received approval to proceed.
• [x] I have followed the coding standards of the project.
• [x] Tests or benchmarks have been added or updated.
• [ ] Documentation has been updated on https://github.com/wundergraph/cosmo-docs.
• [x] I have read the Contributors Guide.

[github-actions[bot]]

Router image scan passed

:white_check_mark: No security vulnerabilities found in image:

ghcr.io/wundergraph/cosmo/router:sha-b6cf585e07d0a2e60aa319fa5a66d9a422d9d5a3

[github-actions[bot]]

This PR was marked stale due to lack of activity. It will be closed in 14 days.