Bug: cloneDeep does not respect instances of classes (affects compat/omit and compat/pick)

[eturino]

this happens with both cloneDeep and compat.cloneDeep.

It is then affecting other functions like omit.

it('should work with custom classes', () => {
    class CustomTest {
      constructor(public value: number) {}
      myFunc() {
        return `value is ${this.value}`;
      }
    }

    const object = new CustomTest(1);
    const cloned = cloneDeep(object);

    expect(cloned).not.toBe(object);
    expect(cloned).toEqual(object);
    expect(cloned.myFunc()).toBe(object.myFunc()); // <- Error: TypeError: cloned.myFunc is not a function
    expect(cloned.myFunc()).toEqual('value is 1');

    const nested = { customTest: new CustomTest(1) };

    const clonedNested = cloneDeep(nested);

    expect(clonedNested).not.toBe(nested);
    expect(clonedNested).toEqual(nested);
    expect(clonedNested.customTest.myFunc()).toBe(nested.customTest.myFunc());
    expect(clonedNested.customTest.myFunc()).toEqual('value is 1');
  });

[D-Sketon]

maybe same as #777, and #794 can solve it