Fixed a nullref message when the bot is loading medusae. Added support for multiple embeds in features which support custom embeds in the form of

{plainText:text-here, embeds: [embedObject, embedObject, embedObject]}

src/NadekoBot/Common/Medusa/Config/MedusaConfig.cs

@@ -1,4 +1,5 @@
-using Cloneable;
+#nullable enable
+using Cloneable;
 using NadekoBot.Common.Yml;
 
 namespace Nadeko.Medusa;
@@ -10,7 +11,7 @@ public sealed partial class MedusaConfig : ICloneable<MedusaConfig>
     public int Version { get; set; } = 1;
     
     [Comment("List of medusae automatically loaded at startup")]
-    public List<string> Loaded { get; set; }
+    public List<string>? Loaded { get; set; }
 
     public MedusaConfig()
     {