[ACS - Chat] GA Attachments to ChatMessage (#26017)

* Update Swagger for receive image from Teams user

* fix pr comments

* change default api version

* rename contentType to extension

* add back metadata, seem like it was GA-ed previously

* Update communicationserviceschat.json

* remove file from GA

* remove uri format

* Rename enum name to ChatAttachment and revert uri type

* Update communicationserviceschat.json

---------

Co-authored-by: John <109105353+jpeng-ms@users.noreply.github.com>
Co-authored-by: JoshuaLai <9044372+JoshuaLai@users.noreply.github.com>

specification/communication/data-plane/Chat/readme.md

@@ -26,7 +26,7 @@ These are the global settings for the communicationservices.
 
 ``` yaml
 openapi-type: data-plane
-tag: package-2023-11-15-preview
+tag: package-chat-2023-11-07
 ```
 
 
@@ -148,6 +148,17 @@ title:
   Azure Communication Services
 ```
 
+### Tag: package-chat-2023-11-07
+
+These settings apply only when `--tag=package-2023-11-07` is specified on the command line.
+
+``` yaml $(tag) == 'package-chat-2023-11-07'
+input-file:
+  - stable/2023-11-07/communicationserviceschat.json
+title:
+  Azure Communication Services
+```
+
 ---
 
 # Code Generation