Fully qualify C# default values in exported fields.

This avoids issues when the default values rely on using
namespaces.

modules/mono/editor/Godot.NET.Sdk/Godot.SourceGenerators.Sample/ExportedFields.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 
 #pragma warning disable CS0169
@@ -83,6 +84,10 @@ namespace Godot.SourceGenerators.Sample
         [Export] private StringName[] field_StringNameArray = { "foo", "bar" };
         [Export] private NodePath[] field_NodePathArray = { "foo", "bar" };
         [Export] private RID[] field_RIDArray = { default, default, default };
+        // Note we use Array and not System.Array. This tests the generated namespace qualification.
+        [Export] private Int32[] field_empty_Int32Array = Array.Empty<Int32>();
+        // Note we use List and not System.Collections.Generic.
+        [Export] private int[] field_array_from_list = new List<int>(Array.Empty<int>()).ToArray();
 
         // Variant
         [Export] private Variant field_Variant = "foo";