fix: revert runOnce breaking changes

[sheerlox]

Description, Motivation & Context

This PR restores the original runOnce property, which was changed in #740 without considering it a breaking change since it was an undocumented internal property. That was a mistake because consumers relied on it. The property was added back as a read-only getter in #751, which was another naive decision from me, because not only did consumers rely on reading it, but it seems (based on the Renovate passing tests percentage below) that they actually also mutate the property to change their jobs' behavior.

Related Issues

• 739

• 740

• 751

How Has This Been Tested?

Test case already present from #740.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [x] All new and existing tests passed.
• [ ] If my change introduces a breaking change, I have added a ! after the type/scope in the title (see the Conventional Commits standard).

[ncb000gt]

:tada: This PR is included in version 3.1.6 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: