fix: Capture groups should be ignored in replace when literal=True

[corwinjoy]

Followup to #19366

in replace, when literal=True, then capture groups should be ignored.

I missed that in the original bug report, #18238, the capture group issue affects replace in addition to replace_all.
This fixed the capture group logic for replace.

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 80.02%. Comparing base (69c9c3a) to head (43f5d92).
Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
...rates/polars-plan/src/dsl/function_expr/strings.rs	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #19413      +/-   ##
==========================================
- Coverage   80.03%   80.02%   -0.02%     
==========================================
  Files        1532     1532              
  Lines      210749   210750       +1     
  Branches     2442     2442              
==========================================
- Hits       168676   168652      -24     
- Misses      41518    41543      +25     
  Partials      555      555              

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