note that deferred callback can only have ephemeral as flag

[Lulalaby]

I believe this is not noted anywhere.

Trying to set the suppress notification flag and the ephemeral flags while deferring ends up being filtered to just the ephemeral flag.

Tested with:

[SlashCommand("test", "Testing")]
public static async Task TestAsync(InteractionContext ctx)
{
        var builder = new DiscordInteractionResponseBuilder().AsEphemeral().AsSilentMessage().SuppressEmbeds().WithV2Components();
        var response = await ctx.CreateResponseAsync(InteractionResponseType.DeferredChannelMessageWithSource, builder);
        await ctx.EditResponseAsync($"Send the following flags: {response.SendFlags}\nReceived the following flags from the callback response: {response.Message?.Flags}");
}