chore: clean up ASN-related code

[Ashka59]

This pull request performs minor code cleanups and modernization in the ASN-related classes:

• In AsnInfo.java, removed an unused import.
• In AsnInfoProviderImplTest.java, removed the 'public' modifier.
• In AsnInfoProviderImpl.java, applied several refactorings: (Renamed variables record to csvRecord, used pattern matching with instanceof for more concise type checks and casts, used _ for unused lambda and exception variables)

These changes improve code readability and maintainability without affecting functionality.