[7948] Remove hard-coded sign_off_period settings

[tomtrentham]

Context

Trello card

Changes proposed in this pull request

• Remove hard-coded sign_off_period settings

Guidance to review

• Does the correct content appear?

Important business

• Does this PR introduce any PII fields that need to be overwritten or deleted in db/scripts/sanitise.sql?
• Does this PR change the database schema? If so, have you updated the config/analytics.yml file and considered whether you need to send 'import_entity' events?
• Do we need to send any updates to DQT as part of the work in this PR?
• Does this PR need an ADR?

NB: Please notify the #twd_data_insights team and ask for a review if new fields are being added to analytics.yml

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.17%. Comparing base (07229a8) to head (53e16d7).
Report is 13 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4908      +/-   ##
==========================================
+ Coverage   96.11%   96.17%   +0.06%     
==========================================
  Files         745      745              
  Lines       16069    16066       -3     
==========================================
+ Hits        15444    15451       +7     
+ Misses        625      615      -10     

Flag	Coverage Δ
unittests	96.17% <ø> (+0.06%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

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

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud