Specify named param for field defaults in Python Pydantic V1 generator

[nicknotfun]

Type-checkers like pyright require the Field-default by the dataclass decorator to be a named parameter. Using the positional variant will result in it being considered a required parameter.

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh ./bin/configs/*.yaml
  ./bin/utils/export_docs_generators.sh
  

  (For Windows users, please run the script in Git BASH)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• File the PR against the correct branch: master (upcoming 7.1.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

@cbornet @tomplus @krjakbrjak @fa0311 @multani

[wing328]

thanks for the PR. please follow step 3 to update the samples

[nicknotfun]

Apologies forgot to push, done

[wing328]

thanks for the PR. let's give it a try

[wing328]

have you considered migrating to python client generator to use pydantic v2?

python-pydantic-v1 will eventually be sunset.

[nicknotfun]

have you considered migrating to python client generator to use pydantic v2?

python-pydantic-v1 will eventually be sunset.

That would require migrating our whole codebase to pydantic v2, which is prohibitively annoying at this stage (we do want to do it).

The embedded v1 in the v2 package isn't 100% compatible for us sadly.