Update layer.py add_loss to properly handle when input loss is a list…

[franklin5]

… of scalar tensor

[franklin5]

#21289

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.57%. Comparing base (dfaca0e) to head (68bec66).

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #21291   +/-   ##
=======================================
  Coverage   82.57%   82.57%           
=======================================
  Files         564      564           
  Lines       54677    54677           
  Branches     8500     8500           
=======================================
  Hits        45152    45152           
  Misses       7435     7435           
  Partials     2090     2090           

Flag	Coverage Δ
keras	82.39% <100.00%> (ø)
keras-jax	63.61% <100.00%> (ø)
keras-numpy	58.74% <100.00%> (ø)
keras-openvino	33.04% <0.00%> (ø)
keras-tensorflow	64.02% <100.00%> (ø)
keras-torch	63.68% <100.00%> (ø)

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.