chore: Add Swagger endpoint for updating custom attributes (#10995)

- Add swagger endpoint for updating custom attributes in a conversation

swagger/paths/application/conversation/custom_attributes.yml

@@ -0,0 +1,36 @@
+tags:
+  - Conversations
+operationId: update-custom-attributes-of-a-conversation
+summary: Update Custom Attributes
+description: Updates the custom attributes of a conversation
+security:
+  - userApiKey: []
+  - agentBotApiKey: []
+parameters:
+  - name: data
+    in: body
+    required: true
+    schema:
+      type: object
+      required:
+        - custom_attributes
+      properties:
+        custom_attributes:
+          type: object
+          description: The custom attributes to be set for the conversation
+          example:
+            order_id: "12345"
+            previous_conversation: "67890"
+responses:
+  200:
+    description: Success
+    schema:
+      type: object
+      properties:
+        custom_attributes:
+          type: object
+          description: The custom attributes of the conversation
+  404:
+    description: Conversation not found
+  401:
+    description: Unauthorized