feat: added default valueless Get to IConfiguration for nullables

Engine.Core/Config/BasicConfiguration.cs

@@ -12,17 +12,18 @@ public class BasicConfiguration : IConfiguration
 
     public IReadOnlyDictionary<string, object?> Values => values;
 
-    public T? Get<T>(string key, T? defaultValue = default)
+    public T Get<T>(string key, T defaultValue) => Get<T>(key) ?? defaultValue;
+    public T? Get<T>(string key)
     {
         if (!values.TryGetValue(key, out object? value))
-            return defaultValue;
+            return default;
 
         if (value is T castedObject)
             return castedObject;
 
         try { return (T?)System.Convert.ChangeType(value, typeof(T)); } catch { }
 
-        return defaultValue;
+        return default;
     }
 
     public object? Get(string key)