diffoscopeMinimal: move libcaca to bloat to remove graphics libraries from runtime

The following dependency chain was created in the last staging-next run
which made diffoscopeMinimal require some graphics libraries which are normally
only required on graphical linux systems and do not fit the minimal suffix.

diffoscopeMinima -> libcaca -> imlib2 -> librsvg -> cairo,pango,etc.

pkgs/tools/misc/diffoscope/default.nix

@@ -46,7 +46,7 @@ python3Packages.buildPythonApplication rec {
   pythonPath = [
       binutils-unwrapped bzip2 colordiff coreutils cpio db diffutils
       e2fsprogs file findutils fontforge-fonttools gettext gnutar gzip
-      libarchive libcaca lz4 openssl pgpdump sng sqlite squashfsTools unzip xxd
+      libarchive lz4 openssl pgpdump sng sqlite squashfsTools unzip xxd
       xz zip zstd
     ]
     ++ (with python3Packages; [
@@ -56,7 +56,7 @@ python3Packages.buildPythonApplication rec {
     ++ lib.optionals stdenv.isLinux [ python3Packages.pyxattr acl cdrkit dtc ]
     ++ lib.optionals enableBloat ([
       abootimg apksigner apktool cbfstool colord enjarify ffmpeg fpc ghc ghostscriptX giflib gnupg gnumeric
-      hdf5 imagemagick llvm jdk mono ocaml odt2txt oggvideotools openssh pdftk poppler_utils procyon qemu R tcpdump ubootTools wabt radare2 xmlbeans
+      hdf5 imagemagick libcaca llvm jdk mono ocaml odt2txt oggvideotools openssh pdftk poppler_utils procyon qemu R tcpdump ubootTools wabt radare2 xmlbeans
     ] ++ (with python3Packages; [ androguard binwalk guestfs h5py pdfminer ]));
 
   checkInputs = with python3Packages; [ pytestCheckHook ] ++ pythonPath;