Create Package during Model Version creation

What does this MR do and why?

This MR addresses the first part of CreateModelVersionService should also create pa... (#433103 - closed) by adding a step to the CreateModelVersionService to find or create the backend package entry in the DB. This change also wraps the service in a transaction since the process updates records in different table.

How to set up and validate locally

1. In the Rails console, ensure the feature flag is enabled

   Feature.enable(:ml_experiment_tracking)

2. In the Rails console, run the following to create a model and a model version:

   project = Project.last # or find a project locally you want to use
   model = Ml::CreateModelService.new(project, 'my-model').execute
   model.versions.create(version: '1.0.0', project: project)

3. In the Rails console, use the CreateModelVersionService to create a new version of model.

   Ml::CreateModelVersionService.new(model).execute
   model.versions.last.package # package should exist

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.