[okhttp-gson] Optimize Imports

[Chrimle]

Removes the unused imports java.util.Map and com.google.gson.JsonArray from generated record classes.

Checklist

Each item in the list MUST either be checked ([x]) or crossed off (~).

• Closes [okhttp-gson] Optimize Imports #408
• New Release?
  • Update <version> in pom.xml
    

    To update the project version, run the following command locally: mvn versions:set -DnewVersion=

  • Update <version> in README.md and index.md
    

    Manually update the project version in documentation files.

• Compile the project with mvn clean install
• Commit all new/changed/deleted generated-sources-files
• Documentation (README.md & index.md) have been updated