Added converter to improve object serialization

src/ElectronNET.API/API/Entities/PageSize.cs

@@ -0,0 +1,20 @@
+namespace ElectronNET.API.Entities;
+
+public class PageSize
+{
+    private readonly string _value;
+
+    public PageSize()
+    {
+    }
+
+    private PageSize(string value) : this() => _value = value;
+
+    public double Height { get; set; }
+
+    public double Width { get; set; }
+
+    public static implicit operator string(PageSize pageSize) => pageSize?._value;
+
+    public static implicit operator PageSize(string value) => new(value);
+}