`banner` and `accent_color` are always `null` on a message author via REST

[Jiralite]

Description

banner and accent_color are returned for the message author when fetching a message. These properties always seem to be null.

Steps to Reproduce

1. Find a message whose author has either a profile banner or a profile theme set
2. Run the following replacing channel_id with a channel id and message_id with a message id:

   curl 'https://discord.com/api/v10/channels/channel_id/messages/message_id' \
   --request GET \
   --header 'Authorization: Bot <token>'
   

Expected Behavior

The fields should be populated correctly. Perhaps they should even be omitted per https://github.com/discord/discord-api-docs/issues/3898#issuecomment-947900146.

Current Behavior

Both fields are always null.

Screenshots/Videos

No response

Client and System Information

curl 8.4.0 (x86_64-apple-darwin23.0) libcurl/8.4.0 (SecureTransport) LibreSSL/3.3.6 zlib/1.2.12 nghttp2/1.58.0