Bug 2037926 - generate file-specific version_bump scopes for landoscript

[JohanLorenzo]

Summary

• build_lando_payload: replaces project:releng:lando:action:version_bump with project:releng:lando:action:version_bump:file:<path> for each file in bump-files
• All other lando action scopes are unchanged
• Updates test_lando_version_bump to expect the new file-specific scope format

Merge order

1. fxci-config staging #1012 — apply-staging + merge first
2. scriptworker-scripts #1448 — deploy to staging, merge
3. fxci-config production #1038 — after staging verification
4. This PR — merge + publish new version
5. xpi-manifest — update mozilla-taskgraph pin, trigger staging e2e test
6. firefox gecko_taskgraph — Phabricator + uplift
7. fxci-config cleanup (separate PR) — remove old general version_bump grants
8. scriptworker-scripts cleanup (separate PR) — remove transition fallback from validate_scopes

Verification

All 69 unit tests pass:

uv run pytest test/ -v

Taskgraph validation in xpi-manifest (using --with-editable) confirms the version-bump-newtab task scopes are now:

[
  "project:releng:lando:action:version_bump:file:browser/extensions/newtab/manifest.json",
  "project:releng:lando:repo:firefox-main"
]

Bug 2037926

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.39%. Comparing base (cddf8e1) to head (1e9eb19).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #215      +/-   ##
==========================================
+ Coverage   98.38%   98.39%   +0.01%     
==========================================
  Files          10       10              
  Lines         495      499       +4     
  Branches       86       87       +1     
==========================================
+ Hits          487      491       +4     
  Misses          2        2              
  Partials        6        6              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[bhearsum]

Seems fine. I want to call out that there's a possibility that this (or another patch) may cause complications on esr115 when you backport. If it does, I suggest hacking around it in that repository rather than trying to support the now-deprecated version_bump scope for the lifetime of esr115.