Merge train should create an MR when it finds a conflict
Summary
Currently, when the merge train (https://ops.gitlab.net/gitlab-org/merge-train) cannot copy commits from canonical to security, it raises an error and terminates the job. The RM then creates an MR by following documentation (https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/security/how_to_sync_security_with_canonical.md) to fix the conflict.
Proposal
The merge train can create an MR to reduce the work of the RM.