Update InMemorySessionService.java

Author: yongkiy-google

core/src/main/java/com/google/adk/sessions/InMemorySessionService.java

@@ -200,7 +200,6 @@ public Completable deleteSession(String appName, String userId, String sessionId
           // If appSessionsMap is now empty, return null to automatically remove the appName key
           return appSessionsMap.isEmpty() ? null : appSessionsMap;
         });
-    
     return Completable.complete();
   }