Migrate more misc ui-test units' levels into ui test partition - #74562

Run bin/curriculum/clone_ui_test_levels.rb on the four remaining ui-test-*
units that still referenced production levels:

  ui-test-unnumbered-lessons
    unnumbered-lesson-level-one -> UI Test unnumbered-lesson-level-one  (new)
  ui-test-versioned-script-2017
    courseB_video_Unspotted     -> UI Test courseB_video_Unspotted      (new)
  ui-test-versioned-script-2019
    courseB_video_Unspotted     -> UI Test courseB_video_Unspotted      (shared)
  ui-test-single-unit-2026
    K-1 Artist1 1               -> UI Test K-1 Artist1 1                (existing)
    Standalone_Artist_9         -> UI Test Standalone_Artist_9          (existing)
    flappy_1                    -> UI Test flappy_1                    (new)
    flappy_11                   -> UI Test flappy_11                   (new)

Four new level files for seven repointed script_levels. The two
versioned-script units share one level, so the second unit lands on the
clone the first one created; the two Artist clones already existed, from
ui-test-csf (#73718) and ui-test-artist earlier in this stack, and were
found by name. That get-or-create by name is what keeps a level shared by
several units to a single copy.

All of these are plain custom levels: no contained levels, no project
templates, no sublevels, no encrypted properties, no rubrics. Each new
clone differs from its source only in name, created_at, updated_at,
audit_log, and the ordering of null-valued properties.

ui-test-shared-unit is already migrated -- #73718 did it as part of that
PR's prove-out -- so it is not touched here. Running the script on it
raises on its first script_level ("UI Test Sample Free Response" already
carries the prefix), which is the guard against double-prefixing.

With this commit, none of the 25 ui-test-* units whose script_json lives
in dashboard/test/ui/config/scripts_json references a production level.
What remains are the deprecated blockly levels of ui-test-maze and
ui-test-shared-unit, which are exempt from the partition.

levelbuilder_mode is off in locals.yml here, so the script was loaded
under `rails runner` with Rails.application.config.levelbuilder_mode set
for that process, as in the parent commits.

Verified:

- Every committed .level file is byte-identical to Level#to_xml for its
  row, at the path Policies::LevelFiles.level_file_path picks: nothing
  here is hand-edited or misfiled.
- Rebuilt from the committed files alone: destroyed the four new clone
  rows, cleared units.md5 on the four units so the incremental seed could
  not skip them, then ran seed:custom_levels_ui_tests and
  seed:reseed_scripts_ui_tests. All four units come back with every
  script_level on a UI Test level and no production level.
- Every migrated level page renders against a local dashboard: all four
  level pages of ui-test-single-unit-2026 and the level page of
  ui-test-unnumbered-lessons and ui-test-versioned-script-2019 return 200
  and serve the clone. ui-test-versioned-script-2017's level page redirects
  to the 2019 version for an unassigned student, as it did before.
- Local UI features, `runner.rb -l` against a dashboard on localhost:3000:
  teacher_tools/unnumbered_lessons.feature (1 scenario),
  teacher_tools/course_overview.feature (5) and
  teacher_tools/course_versions.feature (3) pass, as does the "Unit
  overview for unit in single-unit course" scenario of
  teacher_tools/script_overview.feature, which walks the 2025 -> 2026
  version redirect into ui-test-single-unit-course-2026. Between them these
  load all four units.
- That feature's other two scenarios, "Viewing student progress" and "Unit
  overview contents", fail here for an environmental reason that predates
  the branch: both wait on /courses/allthethingscourse/units/1, which 500s
  on a box with no properties_encryption_key. Two of allthethings'
  LevelGroups are encrypted, so the DSL seed skips their content and
  LevelGroup#pages returns nil under Unit#summarize
  (level_group.rb:113 via script_level.rb:548). Nothing in this commit
  touches allthethings.

Incidental churn in the four script_json files, from re-serializing: a new
serialized_at, a level_keys property on each repointed script_level (set by
the clone script, as in the units migrated by #73718 and #74377), and an
empty jit_pl_concepts_lessons array, a seed model added since these four
files were last written.

[reset db] so drone seeds from empty instead of incrementally, which is
the path a fresh CI container takes.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>