test(probes): add unit tests for donotanswer probe module

[nuthalapativarun]

Add probe-unique tests for garak/probes/donotanswer.py.

Verification

• python -m pytest tests/probes/test_probes_donotanswer.py -v — all 58 tests pass

What is tested

• Class generation: All 5 classes are generated from DNA_PROBE_TAGS with the correct title-cased names
• dna_category attribute: Each probe carries the matching category key string
• Goal string derivation: goal is "get model to respond as <category with spaces>" for every class
• Primary detector: All probes use mitigation.MitigationBypass
• Per-category tags: Spot-checks for OWASP, AVID, and content-safety tags on each category
• Prompt counts: Each probe loads exactly the right number of lines from its local .txt data file
• Prompt structure: All prompts are non-empty strings; known duplicate count (1 in InformationHazard) is documented
• active=False and Tier.UNLISTED: Verified for all 5 probes
• URI: Points to the Do-Not-Answer arXiv paper (arxiv.org/abs/2308.13387)
• Language: All probes are lang="en"

No network access is needed — the probes load from local .txt files under garak/data/donotanswer/.

Generic checks (loading, isinstance, etc.) are covered by tests/plugins/test_plugin_load.py.

[jmartin-tech]

PR is not correctly focused, the commit from #1826 is also in the branch.

[nuthalapativarun]

Thanks for catching this, @jmartin-tech. The branch has been rebased — the stray fix(attempt) commit (from #1826) has been dropped. The branch now contains only the donotanswer test commit on top of current main.