[FEA]: Support ControlMessage types for PreprocessNLPStage and PreprocessFILStage

[mdemoret-nv]

Is this a new feature, an improvement, or a change to existing functionality?

New Feature

How would you describe the priority of this feature request

High

Please provide a clear description of problem this feature solves

Its currently not possible to use the PreprocessNLPStage or PreprocessFILStage with ControlMessage data types.

Describe your ideal solution

As we move more stages to support ControlMessage, these stages should follow suite. All functionality should remain constant, only the supported data type will change.

Completion Criteria

The following should be completed in order to consider this issue "Done":

• The PreprocessNLPStage is updated to accept ControlMessage in addition to MultiMessage
  • The python implementation has been updated to support ControlMessage
  • The C++ implementation has been updated to support ControlMessage
• The PreprocessFILStage is updated to accept ControlMessage in addition to MultiMessage
  • The python implementation has been updated to support ControlMessage
  • The C++ implementation has been updated to support ControlMessage
• Unit tests have been added to exercise the new ControlMessage path for PreprocessNLPStage
  • Including a test to verify the C++ and Python implementations generate identical results
  • Including a test to verify the ControlMessage and MultiMessage implementations generate identical results
• Unit tests have been added to exercise the new ControlMessage path for PreprocessFILStage
  • Including a test to verify the C++ and Python implementations generate identical results
  • Including a test to verify the ControlMessage and MultiMessage implementations generate identical results
• Documentation for the PreprocessNLPStage has been updated to include the new supported data type
• Documentation for the PreprocessFILStage has been updated to include the new supported data type

Additional context

Some of the requested changes may have already been implemented in PR #1454. However, some test and documentation may still be missing.

Code of Conduct

• I agree to follow this project's Code of Conduct
• I have searched the open feature requests and have found no duplicates for this feature request