[system_tests] Fix flaky debugger tests

[vlad-scherbich]

https://datadoghq.atlassian.net/browse/PROF-13796

Motivation

While iterating on PR #6377 (IAST standalone fix), CI repeatedly failed on debugger scenarios (DEBUGGER_TELEMETRY, DEBUGGER_PII_REDACTION, DEBUGGER_PROBES_SNAPSHOT_WITH_SCM, DEBUGGER_SYMDB) across dotnet, java, golang, and python jobs.

Fixing them now to reduces CI noise.

Changes

• DebuggerScenario (utils/_context/_scenarios/debugger.py): library_interface_timeout 5 → 15 seconds for all debugger scenarios.
• debugger_telemetry scenario (utils/_context/_scenarios/__init__.py): library_interface_timeout 5 → 20 seconds (dotnet needs more time for RC + telemetry).
• test_debugger_telemetry.py: Add explicit wait_for_telemetry timeouts (5s default, 25s for dotnet).
• test_debugger_pii.py:
  • Add wait_for_all_probes(statuses=["EMITTING"]) in the retry loop.
  • Add defensive check for missing probe snapshots before iterating (clear AssertionError instead of KeyError).

Reviewer checklist

• Anything but tests/ or manifests/ is modified ? I have the approval from R&P team
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added, removed or renamed?
  • Get a review from R&P team

[github-actions]

CODEOWNERS have been resolved as:

tests/debugger/test_debugger_pii.py                                     @DataDog/debugger @DataDog/system-tests-core
tests/debugger/test_debugger_telemetry.py                               @DataDog/debugger @DataDog/system-tests-core
utils/_context/_scenarios/__init__.py                                   @DataDog/system-tests-core
utils/_context/_scenarios/debugger.py                                   @DataDog/system-tests-core