Policy: Employ db transactions for Policy object Update operations

[ryanulit]

Background

DB transactions support will be officially introduced once PR #1778 is merged. After the merge, we should continue to improve the safety of our DB interactions by employing transactions for existing Update operations that require multiple DB calls for auditing purposes or ACID guarantees.

These should include:

• Safe Update and Deactivation methods
• Unsafe Reactivation methods

Acceptance Criteria

• Transactions used appropriately by methods mentioned above
• Integration tests continue to pass
• No additional integration tests should be necessary, as there is already test coverage for the method providing transactions support