Remove cattrs

[gitttt-1234]

This PR removes cattrs dependency across SLEAP repo.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.45%. Comparing base (7fc9f87) to head (b7318c1).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2446      +/-   ##
===========================================
- Coverage    59.46%   59.45%   -0.01%     
===========================================
  Files           68       68              
  Lines        13222    13216       -6     
===========================================
- Hits          7862     7858       -4     
+ Misses        5360     5358       -2     

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.45%. Comparing base (7fc9f87) to head (b7318c1).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2446      +/-   ##
===========================================
- Coverage    59.46%   59.45%   -0.01%     
===========================================
  Files           68       68              
  Lines        13222    13216       -6     
===========================================
- Hits          7862     7858       -4     
+ Misses        5360     5358       -2     

☔ 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.