[DEVX-2655] Fix in_transaction collisions with other gems

[catks]

There is a name collision for the in_transaction attribute/method in granite and after_commit_everywhere

Changing the private attribute on granite to fix the issue.

Review

• Document code according to Getting Started with Yard.
• All tests are passing.
• Test manually.
• Get approval.

Pre-merge checklist

• The PR relates to a single subject with a clear title and description in grammatically correct, complete sentences.
• Verify that feature branch is up-to-date with master (if not - rebase it).
• Double check the quality of commit messages.
• Squash related commits together.

[catks]

@toptal-anvil ping reviewers