Not supporting adjustable timestep in .org since OpenFOAM 9

[MakisH]

While rebasing the Foundation branches, I noticed that marking the function object methods as final caught an issue: OpenFOAM 9 (and newer) changed the function objects API, which was previously changed in OpenFOAM 6 (at least changes that affect the adapter).

 In file included from preciceAdapterFunctionObject.C:25:
preciceAdapterFunctionObject.H:137:10: error: ‘bool Foam::functionObjects::preciceAdapterFunctionObject::setTimeStep()’ marked ‘final’, but is not virtual
  137 |     bool setTimeStep() final;
      |          ^~~~~~~~~~~
make: *** [/opt/openfoam9/wmake/rules/General/transform:26: Make/linux64GccDPInt32Opt/preciceAdapterFunctionObject.o] Error 1

Compare OpenFOAM8 and OpenFOAM9.

I am removing this function for now. If someone is interested, reimplement.