Remove QLDB

[viren-nadkarni]

AWS retired Quantum Ledger Database (QLDB) on 2025-07-31. It is no longer accessible on AWS and the docs have also been erased.

This PR removes QLDB from Moto.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.87%. Comparing base (e8e5d0c) to head (4760747).
⚠️ Report is 94 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9293      +/-   ##
==========================================
+ Coverage   92.83%   92.87%   +0.04%     
==========================================
  Files        1276     1271       -5     
  Lines      114550   114911     +361     
==========================================
+ Hits       106338   106728     +390     
+ Misses       8212     8183      -29     

Flag	Coverage Δ
servertests	28.76% <ø> (+0.16%)	⬆️
unittests	92.85% <ø> (+0.04%)	⬆️

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.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[bblommers]

Thanks @viren-nadkarni!

Like we already discussed - we'll keep support for QLDB until boto3 drops support for it, but the moment our tests start failing, we'll merge this 👍