[Backport 6.2] fix(nemesis): ignore networkd coredumps during BlockNetwork nemesis

[mergify]

The change adds reducing of coredump event severity during disrupt_network_block disruption, if coredump was triggered by an error in networkd service of
version 255 or lower (the root cause is decribed in #9135).

Fixes: #9135

Testing

• 🟢 longevity-5gb-1h-nemesis.yaml + BlockNetworkMonkey configs
  The CoreDumpEvent events severity is reduced during the test:

❯ grep 'CoreDumpEvent Severity' -rn -A1 sct-runner-events-8e69a961
sct-runner-events-8e69a961/events.log:728:2024-12-10 09:10:06.374: (CoreDumpEvent Severity.WARNING) period_type=one-time event_id=a53eda06-9288-4679-ba76-61781b5cd728 during_nemesis=NetworkBlock node=Node longevity-5gb-1h-BlockNetworkMonkey-db-node-8e69a961-1 [63.33.152.9 | 10.4.20.40]
sct-runner-events-8e69a961/events.log-729-executable=/usr/lib/systemd/systemd-networkd executable_version=255.4
--

PR pre-checks (self review)

• I added the relevant backport labels
• I didn't leave commented-out/debugging code

Reminders

• Add New configuration option and document them (in sdcm/sct_config.py)
• Add unit tests to cover my changes (under unit-test/ folder)
• Update the Readme/doc folder relevant to this change (if needed)

(cherry picked from commit bc96c1c)

Parent PR: #9485

[mergify]

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Changes to be committed:
	modified:   sdcm/coredump.py
	modified:   sdcm/sct_events/system.py
	modified:   unit_tests/test_data/test_coredump/filebased/fail_upload_test_remoter.json
	modified:   unit_tests/test_data/test_coredump/filebased/fail_upload_test_results.json
	modified:   unit_tests/test_data/test_coredump/filebased/success_test_remoter.json
	modified:   unit_tests/test_data/test_coredump/filebased/success_test_results.json
	modified:   unit_tests/test_data/test_coredump/systemd/exceptions_limit_not_reached_test_remoter.json
	modified:   unit_tests/test_data/test_coredump/systemd/exceptions_limit_not_reached_test_results.json
	modified:   unit_tests/test_data/test_coredump/systemd/fail_upload_test_remoter.json
	modified:   unit_tests/test_data/test_coredump/systemd/fail_upload_test_results.json
	modified:   unit_tests/test_data/test_coredump/systemd/success_test_remoter.json
	modified:   unit_tests/test_data/test_coredump/systemd/success_test_results.json
	modified:   unit_tests/test_data/test_coredump/systemd/success_test_systemd_248_remoter.json
	modified:   unit_tests/test_data/test_coredump/systemd/success_test_systemd_248_results.json

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   sdcm/nemesis.py

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[dimakr]

Resolved the conflict.