[csharp][generichost] Fix local var

[devhl-labs]

Partial fix for #19626 Potentially breaking for anyone who has a custom on error implementation.

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
  

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  Commit all changed files.
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[homer-simpson]

Why do you write a “LocalVar” after every local variable? That violates every code convention I know from C# or C++. Sorry, but this makes it unnecessarily difficult to read code and makes it very confusing...

[devhl-labs]

It is a standard in this repo to avoid conflicts with generated variables.