Bug - Entity equals method

Description

The following test fails:

    @Test
    public void equalsTest(){
        var p1 = new ProjectEntity();
        final var fileEntity = new Entity(p1, "init", false, EntityLevel.FILE);
        fileEntity.addMetric(new DoubleMetric(100.0, MetricName.MAINTAINABILITY_INDEX));
        p1.addChild(fileEntity);

        assertThat(p1).isNotEqualTo(new ProjectEntity());
    }

apparently, {set, of, items}.containsAll({}) evaluates to true.

Priority - Medium

This test should not fail

Definition of done

When the test no longer fails