Add conversation_to_link_id parameter to ticket creation API (#317)

Moved conversation_to_link_id parameter from unstable to 2.14 API version. This parameter allows linking conversations to tickets with the following valid combinations:
- conversation | back-office ticket
- customer tickets | non-shared back-office ticket
- conversation | tracker ticket
- customer ticket | tracker ticket

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <[email protected]>

Author: marcmlc

descriptions/2.14/api.intercom.io.yaml

@@ -17892,6 +17892,15 @@ components:
               - email
           example:
           - id: '1234'
+        conversation_to_link_id:
+          type: string
+          description: "The ID of the conversation you want to link to the ticket.
+            Here are the valid ways of linking two tickets:\n
+            - conversation | back-office ticket\n
+            - customer tickets | non-shared back-office ticket\n
+            - conversation | tracker ticket\n
+            - customer ticket | tracker ticket"
+          example: '1234'
         company_id:
           type: string
           description: The ID of the company that the ticket is associated with. The