Refactor: AuthToken 모델 role 필드 제거

Author: wjdrjs00

core/network/src/main/java/com/threegap/bitnagil/network/model/AuthToken.kt

@@ -9,6 +9,4 @@ data class AuthToken(
     val accessToken: String,
     @SerialName("refreshToken")
     val refreshToken: String,
-    @SerialName("role") // todo: 제거 예정
-    val role: String,
 )