[KOTLIN][CLIENT] fix unused library additional properties on kotlin generator

[anantadwi13]

Bugfix for #11327.

Solution

It happens because there is no action to process the library additional properties. In this PR, I propose to add that logic based on this code. I have checked to re-generate kotlin client from the specification yaml. Now It works as expected.

cc @jimschubert @dr4ke616 @karismann @Zomzog @andrewemery @4brunu @yutaka0m

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/utils/export_docs_generators.sh
  

  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*.
  For Windows users, please run the script in Git BASH.
• File the PR against the correct branch: master (5.3.0), 6.0.x
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[4brunu]

Looks good to me 👍