Check Runtime Migration job fails for PRs with companions

[muharem]

check-runtime-migration-* CI jobs fail when companion PRs provided.
The CI job extends the .check-dependent-project job.
The script reports that it can not update the Cargo.lock file since the cargo command run with --locked arg.
For the companion PRs we usually do not commit the Cargo.* files, since they usually contain local machine specific artifacts (from diener tool).

PR example with failing CI jobs:
paritytech/substrate#14434

Failed CI job example:
https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/3296674

[mordamax]

@muharem I didn't know about these CI jobs tbh. now I see that they've been recently added by @liamaharon & @alvicsam here https://github.com/paritytech/substrate/pull/14618/files

@liamaharon @alvicsam could you follow up on this issue, please?

[liamaharon]

I think we need to remove --locked from the runtime migration COMPANION_CHECK_COMMAND command? It doesn't seem to be used in the check-dependent-polkadot which I modelled the new CI job after.

@muharem you can ignore the jobs in your PR for now, and I'll open a PR to remove --locked.

[liamaharon]

@muharem can you check if the fix in this PR resolves your issue? paritytech/substrate#14690