docs: added missing type text for messages (#9067)

- It adds the text type of message which is missing on the documentation

swagger/definitions/request/conversation/create_message.yml

@@ -13,7 +13,7 @@ properties:
     description: Flag to identify if it is a private note
   content_type:
     type: string
-    enum: ['input_email', 'cards', 'input_select', 'form' , 'article']
+    enum: ['text', 'input_email', 'cards', 'input_select', 'form' , 'article']
     example: 'cards'
     description: 'if you want to create custom message types'
   content_attributes:

swagger/swagger.json

@@ -6509,6 +6509,7 @@
         "content_type": {
           "type": "string",
           "enum": [
+            "text",
             "input_email",
             "cards",
             "input_select",