Ignore: 🐛 Fix Chat Room Background Image Process Logic

[psychology50]

작업 이유

• I made a mistake to implement API where updating the chat room information due to the complexity of various scenarios:

	origin image ✅	origin image ❌
non-image	Delete original image	Do nothing
new-image	Delete original image, and copy new image	Copy new image
exist-image	Only check object existence	❌

• However, I was only handling background images with values of null or those starting with the /delete prefix.

작업 사항

• Removed the @Pattern annotation in ChatRoomReq.Update.
• Added the required logic in the ChatRoomPatchHelper.

리뷰어가 중점적으로 확인해야 하는 부분

• none

발견한 이슈

• I also forgot to include the chat member's profile image in the chat member response. ....^^