[Feature] Polls (#2902)

no breakings hopefully

src/Discord.Net.Rest/API/Common/PollMedia.cs

@@ -0,0 +1,12 @@
+using Newtonsoft.Json;
+
+namespace Discord.API;
+
+internal class PollMedia
+{
+    [JsonProperty("text")]
+    public string Text { get; set; }
+
+    [JsonProperty("emoji")]
+    public Optional<Emoji> Emoji { get; set; }
+}