[PERF] Remove stateful actor child materialization limit

[kevinzwang]

Resolves #2900

[codspeed-hq]

CodSpeed Performance Report

Merging #3099 will not alter performance

_{Comparing kevin/actor-pipelining-fix (0bf71c1) with main (9338e2e)}

Summary

✅ 17 untouched benchmarks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.46%. Comparing base (2f09cae) to head (0bf71c1).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3099      +/-   ##
==========================================
+ Coverage   78.36%   78.46%   +0.09%     
==========================================
  Files         612      612              
  Lines       72718    72679      -39     
==========================================
+ Hits        56985    57024      +39     
+ Misses      15733    15655      -78     

Files with missing lines	Coverage Δ
daft/execution/physical_plan.py	93.86% <ø> (-0.03%)	⬇️

... and 10 files with indirect coverage changes