feat(managed): Add helper to get schema size

Author: samyycX

managed/src/SwiftlyS2.Shared/Helper.cs

@@ -88,6 +88,16 @@ public static T AsSchema<T>( nint ptr ) where T : ISchemaClass<T>
         return T.From(ptr);
     }
 
+    /// <summary>
+    /// Get the size of a schema class.
+    /// </summary>
+    /// <typeparam name="T">The schema class to get the size of.</typeparam>
+    /// <returns>The size of the schema class.</returns>
+    public static int GetSchemaSize<T>() where T : ISchemaClass<T>
+    {
+        return T.Size;
+    }
+
     /// <summary>
     /// Estimates the display width of a character based on its type.
     /// Inspired by: https://github.com/spectreconsole/wcwidth