Feat: WebSocketSessionManager 테스트 추가

Author: jueunk617

src/test/java/com/back/domain/chat/controller/ChatWebSocketControllerTest.java renamed to src/test/java/com/back/domain/chat/controller/ChatWebSocketApiControllerTest.java

@@ -30,7 +30,7 @@
 
 @ExtendWith(MockitoExtension.class)
 @DisplayName("ChatWebSocketController 테스트")
-class ChatWebSocketControllerTest {
+class ChatWebSocketApiControllerTest {
 
     @Mock
     private ChatService chatService;