Exception is thrown if the object is without constructor

[danieltrtwn]

Monet.js throws an exception in the following case:

it('should return false for object without constructor', () => {
    const obj = Object.create(null) as object;
    const result = Validation.isInstance(obj); // Exception is thrown
    expect(result).toEqual(false);
});

If you include a check for the constructor property, no exception is thrown and the test is successful:

it('should return false for object without constructor 2', () => {
    const obj = Object.create(null) as object;
    const result = obj.constructor !== undefined && Validation.isInstance(obj);
    expect(result).toEqual(false);
});

Version of monet: 0.9.3
Version of TypeScript: 5.2.2

[ulfryk]

@danieltrtwn please see #258