Modify LSLCMake.cmake install-helper functions to accept COMPONENT argument

[cboulay]

Using LSLCMake.cmake's LSL_install_xyz helper functions will result in an extra installation steps for Unknown components. We can modify the function to accept an argument so the user can optionally specify a component.

function(LSL_install_liblsl)
      cmake_parse_arguments(ARG "" "DESTINATION;FRAMEWORK_DESTINATION;COMPONENT" "" ${ARGN})

      # Build the optional COMPONENT argument list
      set(_component_args "")
      if(ARG_COMPONENT)
          set(_component_args COMPONENT ${ARG_COMPONENT})
      endif()

      if(APPLE)
          # ...
          install(CODE "..." ${_component_args})
      elseif(WIN32)
          if(_lsl_is_fetched)
              install(TARGETS lsl RUNTIME DESTINATION "${ARG_DESTINATION}" ${_component_args})
          else()
              install(IMPORTED_RUNTIME_ARTIFACTS LSL::lsl RUNTIME DESTINATION "${ARG_DESTINATION}" ${_component_args})
          endif()
      else()
          # Linux — same pattern
      endif()
  endfunction()

[cboulay]

Implemented on dev in 7363722a. LSL_install_liblsl and LSL_install_mingw_runtime now accept an optional COMPONENT argument and forward it to their install rules. Omitting the argument preserves the default installation component. Validated named/default component installation and unrelated-component exclusion using Apple, Linux, Windows, and MinGW configuration fixtures.