[feat] DuplicateException, InvalidCreationException 수정

- RuntimeException 을 사용해 @transactional 내의 예상하지 못한 RuntimeException이 발생해도 트랜잭션이 롤백되도록 수정

src/main/java/camp/woowak/lab/customer/exception/DuplicateException.java

@@ -1,4 +1,4 @@
 package camp.woowak.lab.customer.exception;
 
-public abstract class DuplicateException extends Exception {
+public abstract class DuplicateException extends RuntimeException {
 }

src/main/java/camp/woowak/lab/customer/exception/InvalidCreationException.java

@@ -1,6 +1,6 @@
 package camp.woowak.lab.customer.exception;
 
-public class InvalidCreationException extends Exception {
+public class InvalidCreationException extends RuntimeException {
 	public InvalidCreationException(String message) {
 		super(message);
 	}