feat!: drop Is<T> from union types in favour of Value is T

Author: ariesclark

wrapper/VRChat.API/Model/GeneratedModelExtensions.cs

@@ -22,11 +22,6 @@ public abstract partial class AbstractOpenAPISchema
         /// </summary>
         public object Value => ActualInstance;
 
-        /// <summary>
-        /// Whether this instance holds a <typeparamref name="T"/>.
-        /// </summary>
-        public bool Is<T>() => Value is T;
-
         /// <summary>
         /// Gets the <typeparamref name="T"/> this instance holds, if it holds one.
         /// </summary>