Add numerical support for other real types (traffic_flow)

[huiyuxie]

Continue #1909.

Tasks:

• traffic_flow_lwr 1d
• unit tests for above

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.24%. Comparing base (45dfeb4) to head (d171dec).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2020      +/-   ##
==========================================
+ Coverage   96.04%   96.24%   +0.20%     
==========================================
  Files         462      462              
  Lines       37074    37076       +2     
==========================================
+ Hits        35605    35681      +76     
+ Misses       1469     1395      -74     

Flag	Coverage Δ
unittests	96.24% <100.00%> (+0.20%)	⬆️

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[huiyuxie]

Ready for review ^^

[ranocha]

Thanks