Show helper text about merge trains under "Validate the post-merge result would pass prior to merging" option
This was originally requested by @rverissimo at this comment https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14429#note_188848047
Follow-up from "Drop merge train option from project level config"
The following discussion from !14429 (merged) should be addressed:
How can we indicate to users that Merge Trains is the default strategy once we remove it completely from the settings page? I believe this can become confusing once we start making references to
merge trainsin the application's UI.
Proposal: Keep the Merge Trains section in the project settings, so that user knows that this is the default strategy. User cannot turn it on/off, but is still able to visualize it as a merge option.