Revert "CMake: add harvesting of fmt library"

This reverts commit 7c55a7ccca. `fmt` is
only a build-time OIIO dependency and doesn't need to be bundled with
Blender.

build_files/build_environment/cmake/harvest.cmake

@@ -71,8 +71,6 @@ harvest(imath/include imath/include "*.h")
 harvest(imath/lib imath/lib "*.a")
 harvest(ffmpeg/include ffmpeg/include "*.h")
 harvest(ffmpeg/lib ffmpeg/lib "*.a")
-harvest(fmt/include fmt/include "*.h")
-harvest(fmt/lib fmt/lib "*.a")
 harvest(fftw3/include fftw3/include "*.h")
 harvest(fftw3/lib fftw3/lib "*.a")
 harvest(flac/lib sndfile/lib "libFLAC.a")