Added a test table with default values to Codegen.Tests

Author: rekhoff

crates/bindings-csharp/Codegen.Tests/fixtures/diag/Lib.cs

@@ -1,3 +1,4 @@
+using System.ComponentModel;
 using SpacetimeDB;
 
 public enum LocalEnum { }
@@ -361,6 +362,19 @@ public static partial class InAnotherNamespace
     public partial struct TestDuplicateTableName { }
 }
 
+[SpacetimeDB.Table]
+public partial struct TestDefaultFeildValues
+{
+    [Unique]
+    public int? UniqueField;
+
+    [Default(5)]
+    public int IntFeildWithDefault;
+    
+    [Default("Attribute defined default value")]
+    public string StringFeildWithDefault;
+}
+
 [SpacetimeDB.Table]
 [SpacetimeDB.Index.BTree(Name = "TestIndexWithoutColumns")]
 [SpacetimeDB.Index.BTree(Name = "TestIndexWithEmptyColumns", Columns = [])]