fix: Remove accidental todo! in repeat node

[orlp]

Silly mistake by me, not caught because we still use POLARS_AUTO_NEW_STREAMING which automatically defers todo!s to the in-memory engine.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.41%. Comparing base (867443c) to head (3323d0a).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #23822   +/-   ##
=======================================
  Coverage   81.40%   81.41%           
=======================================
  Files        1653     1653           
  Lines      224493   224494    +1     
  Branches     2873     2873           
=======================================
+ Hits       182743   182761   +18     
+ Misses      41036    41019   -17     
  Partials      714      714           

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