Remove unnecessary floating point comparison in radial initialization.

[cgyurgyik]

before:

  if (t_sphere_entrance < t_begin && t_sphere_exit < t_begin) {
    return {};
  }

after:

  if (t_sphere_exit < t_begin) {
    return {};
  }

It is perfectly reasonable for the ray to enter the sphere before t_begin. There is no need to check this.

• Update the CI tests readability and reduce duplication and complexity.