refactor: move replace to FrozenModel

[tlambert03]

this moves the replace method to the frozen base model, and removes the kwargs from the signature

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01 ⚠️

Comparison is base (a904ae3) 96.34% compared to head (329d1a4) 96.33%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #104      +/-   ##
==========================================
- Coverage   96.34%   96.33%   -0.01%     
==========================================
  Files          12       12              
  Lines         738      736       -2     
==========================================
- Hits          711      709       -2     
  Misses         27       27              

Impacted Files	Coverage Δ
src/useq/_base_model.py	88.31% <100.00%> (+0.47%)	⬆️
src/useq/_mda_sequence.py	98.34% <100.00%> (-0.04%)	⬇️

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