fix(BA-3162): Remove agent heartbeat handling observation from audit log

[seedspirit]

resolves #6966 (BA-3162)

Checklist: (if applicable)

• Milestone metadata specifying the target backport version
• Mention to the original issue
• Installer updates including:
  • Fixtures for db schema changes
  • New mandatory config options
• Update of end-to-end CLI integration tests in ai.backend.test
• API server-client counterparts (e.g., manager API -> client SDK)
• Test case(s) to:
  • Demonstrate the difference of before/after
  • Demonstrate the flow of abstract/conceptual models with a concrete implementation
• Documentation
  • Contents in the docs directory
  • docstrings in public interfaces and type annotations

[Copilot]

Pull request overview

This PR removes HandleHeartbeatAction.spec() from the list of supported actions in the agent processors, effectively excluding agent heartbeat handling from being listed as a supported action. This aligns with the treatment of other internal system actions.

• Removes HandleHeartbeatAction from the supported_actions() method return list
• Maintains the actual heartbeat processing functionality (processor still initialized and functional)
• Follows the existing pattern where internal actions like mark_agent_exit and mark_agent_running are also excluded from supported_actions()

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[HyeockJinKim]

Shouldn't we be looking at the part where we're applying action monitors, rather than removing the spec?

[HyeockJinKim]

The implementation is wrong.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

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[HyeockJinKim]

This seems to be the wrong approach.

[fregataa]

1. Using negative phrasing like "SKIP_AUDIT_LOG" in enum names can lead to readability issues, especially when used in conditional statements. But in this case it does not harm readability that much
2. All monitors will be skipped during Heartbeat action handling. Is there any monitors that Heartbeat should be done?

[HyeockJinKim]

I believe that the method is wrong, and it can be applied by excluding the monitor at the time of registration, but adding an additional flag field rather increases complexity. This is a problem that needs to be handled differently during registration, not by adding tags or the like and applying them differently after registration.

[fregataa]

In my opinion, the action should determine whether it should be excluded by a certain rather than the processor. How do you think? @HyeockJinKim