Gitlab Import/Export & Custom Templating misses MR Settings for Squash and Merge Commit Templates

Summary

When using the export and import function of gitlab, custom project settings for "Merge commit message template" and "Squash commit message template" will be lost and not set for the new project. As the import/export is also used for creating custom Templates we are also facing this issue with EE custom Templates.

Steps to reproduce

1. Set custom Merge and/or Squash commit message template to a custom value under Settings > Merge requests
2. Create a new project based on the first on, using one of the following ways
3. Export first project and import the exported .tar.gz as new project
4. (EE) Use the first project as custom Template and create a new project with this template
5. Check the Merge requests settings in the new project

Example Project

Not a specific Project, but happens on gitlab.com(2.11.2023) and gitlab-ee(16.3.4-ee)

What is the current bug behavior?

The new project has the default values

What is the expected correct behavior?

The new projects settings are the same as the exported/template

Possible fixes

https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/import_export/project/import_export.yml?ref_type=heads is missing the the keys for both fields