[externals] remove SPIRV-Headers and SPIRV-Tools (#3989)

only dep that uses it is sirit, but sirit already has it's own bundled SPIRV-Headers... so

Signed-off-by: lizzie <[email protected]>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3989
Reviewed-by: Maufeat <[email protected]>
Reviewed-by: CamilleLaVey <[email protected]>

shell.nix

@@ -13,7 +13,7 @@ pkgs.mkShellNoCC {
     # libraries
     openssl boost fmt nlohmann_json lz4 zlib zstd
     enet libopus vulkan-headers vulkan-utility-libraries
-    spirv-tools spirv-headers vulkan-loader unzip
+    vulkan-loader unzip
     glslang python3 httplib cpp-jwt ffmpeg-headless
     libusb1 cubeb
     # eden