Allow ability to disable pipelines for merge requests from running in target projects via project settings
GitLab released a feature in 13.3 which allows some pipelines from merge requests to run in the context of the target project [1]. However, it might be the case that even internal contributors (those that have the "Developer" role or higher on the target project) might want to run pipelines in the context of the source project, not the target project. In this case, all engineers' pipelines (regardless of role) will run with the same context: the source project's context.
Adding the ability to turn this feature off via a project-specific configuration would support this.