fix: make /opt-in and /opt-out's responses ephemeral

src/command/opt_in.rs

@@ -5,6 +5,7 @@ use twilight_model::{
         command::{Command, CommandType},
         interaction::Interaction,
     },
+    channel::message::MessageFlags,
     http::interaction::{InteractionResponse, InteractionResponseType},
 };
 use twilight_util::builder::{InteractionResponseDataBuilder, command::CommandBuilder};
@@ -79,6 +80,7 @@ pub async fn handle(state: State, interaction: Interaction) {
                         .content(format!(
                             "opted you in, your previous consent was {previous_consent:?}"
                         ))
+                        .flags(MessageFlags::EPHEMERAL)
                         .build(),
                 ),
             },