Add Object expression to API client

src/clients/Elsa.Api.Client/Converters/ExpressionJsonConverter.cs

@@ -51,6 +51,7 @@ public class ExpressionJsonConverter : JsonConverter<IExpression>
             "Literal" => typeof(LiteralExpression),
             "JavaScript" => typeof(JavaScriptExpression),
             "Liquid" => typeof(LiquidExpression),
+            "Object" => typeof(ObjectExpression),
             _ => throw new ArgumentOutOfRangeException(nameof(expressionTypeName), expressionTypeName, null)
         };
     
@@ -60,6 +61,7 @@ public class ExpressionJsonConverter : JsonConverter<IExpression>
             nameof(LiteralExpression) => "Literal",
             nameof(JavaScriptExpression) => "JavaScript",
             nameof(LiquidExpression) => "Liquid",
+            nameof(ObjectExpression) => "Object",
             _ => throw new ArgumentOutOfRangeException(nameof(expressionType), expressionType, null)
         };
 }

src/clients/Elsa.Api.Client/Expressions/ObjectExpression.cs

@@ -0,0 +1,36 @@
+using System.Text.Json.Serialization;
+using Elsa.Api.Client.Contracts;
+
+namespace Elsa.Api.Client.Expressions;
+
+/// <summary>
+/// Represents an object expression formatted as a string value.
+/// </summary>
+public class ObjectExpression : IExpression
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ObjectExpression"/> class.
+    /// </summary>
+    [JsonConstructor]
+    public ObjectExpression()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ObjectExpression"/> class.
+    /// </summary>
+    public ObjectExpression(string? value)
+    {
+        Value = value;
+    }
+    
+    /// <summary>
+    /// The literal value.
+    /// </summary>
+    public string? Value { get; set; }
+
+    /// <summary>
+    /// Returns the string representation of the expression.
+    /// </summary>
+    public override string ToString() => Value?.ToString() ?? "";
+}