refactor: 테스트에서의 region 테이블 FK 충돌 해결로 인한 값 재설정

src/test/kotlin/roomescape/util/Fixtures.kt

@@ -72,7 +72,7 @@ object UserFixture {
         email: String = "sample@example.com",
         password: String = "a".repeat(MIN_PASSWORD_LENGTH),
         phone: String = "01012345678",
-        regionCode: String? = null,
+        regionCode: String = "1111010100",
         status: UserStatus = UserStatus.ACTIVE
     ): UserEntity = UserEntity(
         id = id,
@@ -89,7 +89,7 @@ object UserFixture {
         email = "sample@example.com",
         password = "a".repeat(MIN_PASSWORD_LENGTH),
         phone = "01012345678",
-        regionCode = null
+        regionCode = "1111010100"
     )
 }