feat: scatter add gradient

[avik-pal]

fixes #1423

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 42.53%. Comparing base (c9e136c) to head (27d639f).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1609      +/-   ##
==========================================
- Coverage   42.59%   42.53%   -0.07%     
==========================================
  Files         123      123              
  Lines       21887    21887              
==========================================
- Hits         9323     9309      -14     
- Misses      12564    12578      +14     

☔ 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.