cmake - Fix cmake when urdf support is disabled.

[abussy-aldebaran]

Fix the error:

CMake Error at CMakeLists.txt:247 (if):
  if given arguments:

    "BUILD_WITH_URDF_SUPPORT" "AND" "VERSION_GREATER" "0.4.2"

  Unknown arguments specified

when running cmake -DBUILD_WITH_URDF_SUPPORT=off

[github-actions]

👋 Hi,
This is a reminder message to please assign a proper label to this Pull Request.
The possible labels are:

• build_collision (build pinocchio with coal support)
• build_casadi (build pinoochio with casadi support)
• build_autodiff (build pinocchio with cppad support)
• build_codegen (build pinocchio with cppadcg support)
• build_extra (build pinocchio with extra algorithms)
• build_mpfr (build pinocchio with Boost.Multiprecision support)
• build_sdf (build pinocchio with sdf parser)
• build_accelerate
• build_all (build pinocchio with all the options stated above)

Thanks.