[v18] Proxy Recording fixes

[Joerger]

Changelog: Fix a bug in Proxy recording mode where Teleport Node sessions would result in duplicate audit events with a different session ID.

Backport #58707, #59610, #59206, #59850 to branch/v18

I decided to backport these together so that I can manually test them all together, since many of the changes overlap and build upon each other.

Manual Tests

Last run: 2c50e61

• Proxy recording mode:
  • Teleport Node
    • Start a session and use teleport status to get the session ID. it should appear in the session list (e.g. tsh session ls).
    • End the session. Observe session start, end, data, and leave events are emitted with the same session ID.
      • No duplicate events
      • these events should have the forwarded_by and recording_mode: proxy fields.
      • Other event fields should reference the target node (addr.local, server_id, server_addr)
  • Teleport Node (tunnel / different process)
    • Start a session and use teleport status to get the session ID. it should appear in the session list (e.g. tsh session ls).
    • End the session. Observe session start, end, data, and leave events are emitted with the same session ID.
      • No duplicate events
      • these events should have the forwarded_by and recording_mode: proxy fields.
      • Other event fields should reference the target node (addr.local, server_id, server_addr)
  • Agentless Node
    • Start a session and use teleport status to get the session ID. it should appear in the session list (e.g. tsh session ls).
    • End the session. Observe session start, end, data, and leave events are emitted with the same session ID.
      • these events should have the forwarded_by and recording_mode: proxy fields.
      • Other event fields should reference the target node (addr.local, server_id, server_addr)
• Node recording mode:
  • Teleport Node
    • Start a session and use teleport status to get the session ID. it should appear in the session list (e.g. tsh session ls).
    • End the session. Observe session start, end, data, and leave events are emitted with the same session ID.
      • these events should not have the forwarded_by and recording_mode: proxy fields.
      • Other event fields should reference the target node (addr.local, server_id, server_addr)
• Teleport Node (tunnel / different process)
  • Start a session and use teleport status to get the session ID. it should appear in the session list (e.g. tsh session ls).
  • End the session. Observe session start, end, data, and leave events are emitted with the same session ID.
    • No duplicate events
    • these events should not have the forwarded_by and recording_mode: proxy fields.
    • Other event fields should reference the target node (addr.local, server_id, server_addr)
  • Agentless Node
    • Start a session and use teleport status to get the session ID. it should appear in the session list (e.g. tsh session ls).
    • End the session. Observe session start, end, data, and leave events are emitted with the same session ID.
      • these events should have the forwarded_by and recording_mode: proxy fields.
      • Other event fields should reference the target node (addr.local, server_id, server_addr)

Backwards compatibility:

Proxy	Node	Mismatched ID w/ tracker	Duplicate events	✅
new	new	no	no	✅
new	old	no	yes	✅
old	new	yes	no	✅
old	old	yes	yes	✅

Teleport Cloud smoke tests:

• Connect to Teleport Node, check session recording and audit log for expected results