Temporarily remove Scotland population live test

[anth-volk]

Fixes #3874

Temporarily remove the Scotland population live test that fails because the simulation worker filters UK household inputs by a nonexistent country column. This intentionally leaves that failing population behavior uncovered until the upstream repair is released and deployed. The Scotland household calculation test, Utah and California population tests, and Scotland fixtures remain.

Remove the deleted live function's local request-contract parametrization as well, so unit test collection continues to work. The follow-up API PR will restore both the live test and this parametrization.

Upstream fix: PolicyEngine/policyengine.py#565 (issue PolicyEngine/policyengine.py#564). Release order: merge this temporary removal; publish the corrected .py package (expected 6.2.3); upgrade and deploy the simulation API in PolicyEngine/policyengine-sim-api#733 (issue PolicyEngine/policyengine-sim-api#732); then upgrade API v1 and restore the Scotland population test in #3877 (issue #3876). This PR does not repair the simulation behavior.

Validation: 3 focused live-request unit tests passed; the deployed live suite collects 9 tests, including the Scotland household test. Repository formatting, changed-file Ruff checks, changelog validation, and git diff --check passed. The deployed suite was not executed locally; collecting it does not validate a deployment.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.56%. Comparing base (a7d5af3) to head (a0a0d4d).

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #3875       +/-   ##
===========================================
+ Coverage   45.22%   87.56%   +42.33%     
===========================================
  Files         183      198       +15     
  Lines       11073    12211     +1138     
  Branches     1905     2159      +254     
===========================================
+ Hits         5008    10692     +5684     
+ Misses       5644      922     -4722     
- Partials      421      597      +176     

☔ View full report in Codecov by Harness.
📢 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.