[#12779] Fix notifications update logic

[marquestye]

Part of #12779

Outline of Solution

• Added flushAndEvict to HibernateUtil.java
• During update, evict entity -> call setters -> check validity -> merge entity
• Changed EntitiesDb#merge to print with returned entity to overcome invalid proxy issue for entities with no persistent instance
  • Added required mocks for component tests calling merge
• Added tests for invalid data persistence
• Moved invalid params checks and tests from db to logic layer

[nusoss-bot]

Folks, This PR seems to be stalling (no activities for the past 58 days). :snail: :cry: Hope someone can get it to move forward again soon...

[nusoss-bot]

Folks, This PR seems to be stalling (no activities for the past 7 days). :snail: :cry: Hope someone can get it to move forward again soon...