feat: add exceptions parameter to MustCallInConstructor annotation

Author: mcquenji

lib/src/must_call_in_constructor.dart

@@ -24,8 +24,16 @@ class MustCallInConstructor {
   /// Otherwise, it applies to the class even if it's abstract.
   final bool concreteOnly;
 
+  /// A list of types that are exempt from this requirement.
+  /// If the class using the mixin is a subtype of any of these types,
+  /// the requirement is considered satisfied.
+  final List<Type> exceptions;
+
   /// {@macro hook_installer}
-  const MustCallInConstructor({this.concreteOnly = true});
+  const MustCallInConstructor({
+    this.concreteOnly = true,
+    this.exceptions = const [],
+  });
 }
 
 /// {@macro hook_installer}