note that deferred callback can only have ephemeral as flag (#7386)

* note that deferred callback can only have ephemeral as flag

I believe this is not noted anywhere.
In response to https://canary.discord.com/channels/1317206872763404478/1338540867467612253/1338647116192546878

* Update docs/interactions/Receiving_and_Responding.mdx

---------

Co-authored-by: Austin Keener <[email protected]>

Author: Lulalaby

docs/interactions/Receiving_and_Responding.mdx

@@ -245,12 +245,14 @@ Not all message fields are currently supported.
 | content?          | string                                                                           | Message content                                                                                                                                                                                                        |
 | embeds?           | array of [embeds](#DOCS_RESOURCES_MESSAGE/embed-object)                          | Supports up to 10 embeds                                                                                                                                                                                               |
 | allowed_mentions? | [allowed mentions](#DOCS_RESOURCES_MESSAGE/allowed-mentions-object)              | [Allowed mentions](#DOCS_RESOURCES_MESSAGE/allowed-mentions-object) object                                                                                                                                             |
-| flags?            | integer                                                                          | [Message flags](#DOCS_RESOURCES_MESSAGE/message-object-message-flags) combined as a [bitfield](https://en.wikipedia.org/wiki/Bit_field) (only `SUPPRESS_EMBEDS`, `EPHEMERAL`, and `SUPPRESS_NOTIFICATIONS` can be set) |
+| flags? \*         | integer                                                                          | [Message flags](#DOCS_RESOURCES_MESSAGE/message-object-message-flags) combined as a [bitfield](https://en.wikipedia.org/wiki/Bit_field) (only `SUPPRESS_EMBEDS`, `EPHEMERAL`, and `SUPPRESS_NOTIFICATIONS` can be set) |
 | components?       | array of [components](#DOCS_INTERACTIONS_MESSAGE_COMPONENTS/)                    | Message components                                                                                                                                                                                                     |
-| attachments? \*   | array of partial [attachment](#DOCS_RESOURCES_MESSAGE/attachment-object) objects | Attachment objects with filename and description                                                                                                                                                                       |
+| attachments? \*\* | array of partial [attachment](#DOCS_RESOURCES_MESSAGE/attachment-object) objects | Attachment objects with filename and description                                                                                                                                                                       |
 | poll?             | [poll](#DOCS_RESOURCES_POLL/poll-create-request-object) request object           | Details about the poll                                                                                                                                                                                                 |
 
-\* See [Uploading Files](#DOCS_REFERENCE/uploading-files) for details.
+\* If you create a callback with the [type](#DOCS_INTERACTIONS_RECEIVING_AND_RESPONDING/interaction-response-object-interaction-callback-type) `DEFERRED_CHANNEL_MESSAGE_WITH_SOURCE` the only valid [message flag](#DOCS_RESOURCES_MESSAGE/message-object-message-flags) you may use is `EPHEMERAL`.
+
+\*\* See [Uploading Files](#DOCS_REFERENCE/uploading-files) for details.
 
 ###### Autocomplete