Improve code generation with fixes for recursion, aliasing, and modular references

[sternakt]

This PR introduces multiple improvements, bug fixes, and refactoring efforts focused on enhancing code generation and resolving several issues related to parsing and argument handling.

• Updated datamodel-code-generator
Upgraded the dependency to leverage improved modular reference support.
• Refactored parsing and operation logic
  • Refactored Operation.arguments and Operation.snake_case_arguments for better structure and readability.
• Recursion Error & Duplicate Arguments
Resolved issues where recursive parsing or duplicate function arguments could occur.
• Aliased Imports
  • Introduced a temporary patch_parse function that solves the issue with shadowed imports.
  • Fixed issues with shadowed or aliased imports that caused incorrect code generation.

Added new test examples for discovered failing cases:

• tests/data/openapi/default_template/discriminator_in_root_with_properties.yaml
• tests/data/openapi/default_template/duplicate_anonymus_parameter.yaml
• tests/data/openapi/default_template/duplicate_param.yaml
• tests/data/openapi/default_template/modular_reference.yaml
• tests/data/openapi/default_template/recursion.yaml
• tests/data/openapi/default_template/shadowed_imports.yaml

[codecov]

Codecov Report

Attention: Patch coverage is 90.27027% with 18 lines in your changes missing coverage. Please review.

Project coverage is 90.59%. Comparing base (3342f58) to head (748151b).
Report is 31 commits behind head on master.

Files with missing lines	Patch %	Lines
fastapi_code_generator/parser.py	81.35%	11 Missing ⚠️
fastapi_code_generator/patches.py	94.01%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #484      +/-   ##
==========================================
+ Coverage   89.78%   90.59%   +0.81%     
==========================================
  Files           5        7       +2     
  Lines         421      585     +164     
==========================================
+ Hits          378      530     +152     
- Misses         43       55      +12     

Flag	Coverage Δ
unittests	90.59% <90.27%> (+0.81%)	⬆️

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