Fix Ambiguous @ExceptionHandler for AsyncRequestNotUsableException in CustomExceptionHandler

Problem

CustomExceptionHandler extends ResponseEntityExceptionHandler and declares AsyncRequestNotUsableException in handleClientAbort's @ExceptionHandler.

Spring 6.2.x added AsyncRequestNotUsableException handling to ResponseEntityExceptionHandler.handleException(), causing an ambiguous mapping conflict on startup:

Ambiguous @ExceptionHandler method mapped for AsyncRequestNotUsableException:
- CustomExceptionHandler.handleClientAbort
- ResponseEntityExceptionHandler.handleException

Solution

Remove AsyncRequestNotUsableException.class from handleClientAbort's @ExceptionHandler. The parent class already handles it with equivalent behavior (silent handling for client disconnect).

Affected file

web/src/main/java/com/navercorp/pinpoint/web/problem/CustomExceptionHandler.java