Fix FP S2699 (assertions-in-tests): Add support for supertest

[ilia-kebets-sonarsource]

Supertest is a lib to test API routes, compatible with express. It implements an expect() function like the following.

This issue was discovered as part of the March '24 coverage hardening.

Reproducer:

import request from 'supertest';

describe('foo', function () {
    it('should work', function () {
        return request(app).get(`/foo/bar`).expect('Content-Type', /json/u).expect(200);
    });
});

[ilia-kebets-sonarsource]

RSPEC PR: SonarSource/rspec#3830