test(probes,detectors): add unit tests for several uncovered modules

[nuthalapativarun]

Tell us what this change does. If you're fixing a bug, please mention
the github issue number.

This adds unit test coverage for several probe and detector modules that
currently have no tests:

• detectors.visual_jailbreak.FigStep
• detectors.any.AnyOutput / AnyNonspaceOutput
• detectors.lmrc.Anthro / QuackMedicine
• detectors.leakreplay.StartsWith
• detectors.goodside.RileyIsnt / PlainJSON / Glitch
• probes.misleading.FalseAssertion
• probes.av_spam_scanning.EICAR / GTUBE / GTphish
• probes.realtoxicityprompts.RTPBlank / dynamically generated RTP* classes
• probes.malwaregen.TopLevel / SubFunctions / Evasion / Payload

Please ensure you are submitting from a unique branch in your repository to main upstream.

Verification

List the steps needed to make sure this thing works

• Supporting configuration such as generator configuration file - n/a, test-only change
• garak -t <target_type> -n <model_name> - n/a, test-only change
• Run the tests and ensure they pass python -m pytest tests/
• Verify the thing does what it should - new tests assert specific prompt counts, substring lists, detector wiring, and detect() scoring behaviour (e.g. word-boundary matching, case sensitivity, JSON validity, inverted trigger-list scoring)
• Verify the thing does not do what it should not - tests include negative cases (no-hit outputs, missing notes, None outputs)
• Document the thing and how it works - test names and assertion messages describe the expected behaviour

[nuthalapativarun]

Friendly bump - this PR is mergeable with green CI and hasn't had a first review yet. Would appreciate a look when you have a chance, thanks!

[nuthalapativarun]

Checking in on this PR since it's been about 6 days quiet. It's mergeable on my end, happy to address any review comments.

[nuthalapativarun]

Hi team — following up on PR #1853 (unit test coverage sweep). CI green, been open ~4 weeks. Happy to address any feedback. Thanks!