Install ms-gsl from pix for mac-arm (#9)

Summary:
Pull Request resolved: #9

Installing `ms-gsl` from Pixi is now supported on mac-arm as well, by conda-forge/ms-gsl-feedstock#1

Differential Revision: D58748282

pixi.toml

@@ -30,6 +30,7 @@ ezc3d = "1.5.9.*"
 fmt = "10.2.1.*"
 libdeflate = ">=1.19,<2"
 librerun-sdk = ">=0.16,<0.17"
+ms-gsl = ">=4.0.0,<4.1"
 nlohmann_json = "3.11.*"
 openssl = ">=3.2.1,<3.3"
 re2 = "2023.9.1.*"
@@ -65,11 +66,6 @@ install_sophus = { cmd = "git clone https://github.com/strasdat/Sophus.git -b '1
 ], outputs = [
     "$CONDA_PREFIX/share/sophus/cmake/SophusConfig.cmake",
 ] }
-install_ms_gsl = { cmd = "git clone https://github.com/microsoft/GSL.git -b 'v4.0.0' --single-branch --depth 1 && cmake GSL -B GSL/build -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX -DCMAKE_BUILD_TYPE=Release -DGSL_TEST=OFF && cmake --build GSL/build --target install --parallel && rm -rf GSL", cwd = ".deps", depends_on = [
-    "create_deps_dir",
-], outputs = [
-    "$CONDA_PREFIX/share/cmake/Microsoft.GSL/Microsoft.GSLConfig.cmake",
-] }
 install_deps = { depends_on = [
     "install_drjit",
     "install_dispenso",
@@ -108,7 +104,6 @@ install = { cmd = "cmake --build build -j --target install", depends_on = [
 clang-format-18 = ">=18.1.2,<19"
 
 [target.linux-64.dependencies]
-ms-gsl = ">=4.0.0,<4.1"
 pytorch = ">=2.1.2,<2.2"
 sophus = ">=22.10,<23"
 sysroot_linux-64 = ">=2.28"
@@ -141,7 +136,6 @@ install_deps = { depends_on = [
     "install_OpenFBX",
     "install_fx_gltf",
     "install_sophus",
-    "install_ms_gsl",
     "remove_deps_dir",
 ] }
 lint = { cmd = "clang-format-18 -i axel/**/*.h axel/**/*.cpp momentum/**/*.h momentum/**/*.cpp pymomentum/**/*.h pymomentum/**/*.cpp" }
@@ -155,7 +149,6 @@ build_pymomentum = { cmd = "pip install -e .", depends_on = ["install_deps"] }
 #=========
 
 [target.win-64.dependencies]
-ms-gsl = ">=4.0.0,<4.1"
 pytorch-cuda = ">=12.1,<13"
 
 [target.win-64.tasks]