[misc] Fix cannot name an alias template, fixes #8683

Issue: #8683

### Brief Summary

Compile error, on mac M4 Sequoia:
```
FAILED: taichi/util/CMakeFiles/taichi_util.dir/image_buffer.cpp.o
/Users/hugh/.cache/ti-build-cache/sccache-v041/bin/sccache /usr/bin/clang++  -I/Users/hugh/.cache/ti-build-cache/mambaforge/envs/3.10/lib/python3.10/site-packages/numpy/_core/include -I/Users/hugh/git/taichi -I/Users/hugh/git/taichi/external/include -I/Users/hugh/git/taichi/external/eigen -I/Users/hugh/.cache/ti-build-cache/llvm15-m1-nozstd/include -I/Users/hugh/git/taichi/external/spdlog/include -ffunction-sections -fdata-sections -DTI_ISE_NONE -std=c++17 -fsized-deallocatio
n -Wno-deprecated-declarations -Wno-shorten-64-to-32 -Wall  -Werror  -Wno-ignored-attributes  -Wno-nullability-completeness  -Wno-unused-private-field  -Wno-unneeded-internal-declaration  -Wno-unqualified-std-cast-call  -Wno-unused-but-set-variable  -DTI_ARCH_ARM -DTI_PASS_EXCEPTION_TO_PYTHON -DTI_INCLUDED -fno-objc-arc -DTI_WITH_LLVM -DTI_WITH_METAL -O3 -DNDEBUG -std=gnu++17 -arch arm64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX15.4.sdk -mmacosx-version-min=15
.0 -fPIC -fvisibility=hidden -fvisibility-inlines-hidden   -D_DEBUG -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -MD -MT taichi/util/CM


akeFiles/taichi_util.dir/image_buffer.cpp.o -MF taichi/util/CMakeFiles/taichi_util.dir/image_buffer.cpp.o.d -o taichi/util/CMakeFiles/taichi_util.dir/image_buffer.cpp.o -c /Users/hugh/git/taichi/taichi/util/image_buffer.cpp
/Users/hugh/git/taichi/taichi/util/image_buffer.cpp:21:18: error: a declarative nested name specifier cannot name an alias template [-Werror,-Walias-template-in

-declaration-name]
   21 | void Array2D<T>::load_image(const std::string &filename, bool linearize) {
      |      ~~~~~~~~~~~~^
/Users/hugh/git/taichi/taichi/util/image_buffer.cpp:60:18: error: a declarative nested name specifier cannot name an alias template [-Werror,-Walias-template-in-declaration-name]
   60 | void Array2D<T>::write_as_image(const std::string &filename) {
      |      ~~~~~~~~~~~~^
/Users/hugh/git/taichi/taichi/util/image_buffer.cpp:100:18: error: a declarative nested name specifier cannot name an alias template [-Werror,-Walias-template-in-declaration-name]
  100 | void Array2D<T>::write_text(const std::string &font_fn,
      |      ~~~~~~~~~~~~^
3 errors generated.
```

Fix:
- use the NDArray<2, N> directly, instead of the alias

copilot:summary

### Walkthrough

copilot:walkthrough

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: hughperkins

.github/workflows/scripts/common-utils.sh

@@ -5,15 +5,15 @@ set -x
 function unset-git-caching-proxy {
     echo "Unsetting git caching proxy"
     # git config --global --list | grep 'url\.' | cut -d'=' -f1 | xargs -L1 git config --global --unset-all || true
-    git config --global --unset https.proxy
+    git config --global --unset https.proxy || true
 }
 
 function set-git-caching-proxy {
     trap unset-git-caching-proxy EXIT
     echo "Setting git caching proxy"
     # git config --global --add url.http://oauth2:[email protected]/.insteadOf https://github.com/
     # git config --global --add url.http://oauth2:[email protected]/.insteadOf [email protected]:
-    git config --global https.proxy http://proxy.tgr:18000
+    git config --global https.proxy http://proxy.tgr:18000 ||  true
 }
 
 if [ ! -z "$TI_USE_GIT_CACHE" ]; then

taichi/util/image_buffer.cpp

@@ -18,7 +18,7 @@
 namespace taichi {
 
 template <typename T>
-void Array2D<T>::load_image(const std::string &filename, bool linearize) {
+void ArrayND<2, T>::load_image(const std::string &filename, bool linearize) {
   int channels;
   FILE *f = fopen(filename.c_str(), "rb");
   TI_ASSERT_INFO(f != nullptr, "Image file not found: " + filename);
@@ -57,7 +57,7 @@ void Array2D<T>::load_image(const std::string &filename, bool linearize) {
 }
 
 template <typename T>
-void Array2D<T>::write_as_image(const std::string &filename) {
+void ArrayND<2, T>::write_as_image(const std::string &filename) {
   int comp = 3;
   std::vector<unsigned char> data(this->res[0] * this->res[1] * comp);
   for (int i = 0; i < this->res[0]; i++) {
@@ -97,12 +97,12 @@ std::map<std::string, stbtt_fontinfo> fonts;
 std::map<std::string, std::vector<uint8>> font_buffers;
 
 template <typename T>
-void Array2D<T>::write_text(const std::string &font_fn,
-                            const std::string &content_,
-                            real size,
-                            int dx,
-                            int dy,
-                            T color) {
+void ArrayND<2, T>::write_text(const std::string &font_fn,
+                               const std::string &content_,
+                               real size,
+                               int dx,
+                               int dy,
+                               T color) {
   std::vector<unsigned char> screen_buffer(
       (size_t)(this->res[0] * this->res[1]), (unsigned char)0);