Provide inplace replacement util

[gramalingam]

Redo #2703, thanks to Titai.

[codecov]

Codecov Report

❌ Patch coverage is 40.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.04%. Comparing base (c1bfdfc) to head (4553011).
⚠️ Report is 13 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
onnxscript/utils/replace.py	40.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2708      +/-   ##
==========================================
- Coverage   70.04%   70.04%   -0.01%     
==========================================
  Files         226      226              
  Lines       27177    27179       +2     
  Branches     2734     2734              
==========================================
+ Hits        19036    19037       +1     
- Misses       7197     7198       +1     
  Partials      944      944              

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[Copilot]

Pull Request Overview

This PR refactors the replace_functions utility by extracting the core logic into a new replace_functions_inplace function that operates directly on IR models. The original replace_functions now acts as a wrapper that handles proto conversion and calls the new inplace variant.

Key changes:

• Introduces replace_functions_inplace that operates on ir.Model and ir.Function types directly
• Refactors replace_functions to convert protos and delegate to the inplace function

[justinchuby]

Suggested change

	def replace_functions_inplace(irmodel: ir.Model, irfunctions: Sequence[ir.Function]) -> None:
	def replace_functions_inplace(model: ir.Model, functions: Collection[ir.Function]) -> None:

Consider consistent names