[csharp][generichost] Add options for model parameter sorting

[devhl-labs]

Moves the changes made here #18706 to an option. The plan is to change the sorting method to default when we get to 8.0 with the samples using alphabetical sorting. Some of the samples were changed to alphabetical now because there is a model in the petstore that does not work with legacy.

PR checklist

• Read the contribution guidelines.
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  ./bin/utils/export_docs_generators.sh
  

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  Commit all changed files.
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