Using custom thrust repo

I'm trying to use the latest Thrust release and running into issues.
I can reproduce this in the examples of this repo. See here: https://github.com/garymm/rules_cuda/tree/0b47488/examples

It seems that for some reason the CUDA toolkit's thrust is used, even though the `-isystem` for my custom thrust comes first on the nvcc command.

To reproduce:

```
# First, install any CUDA toolkit at or less than version 12.1
# Then
git clone https://github.com/garymm/rules_cuda.git
cd rules_cuda
git switch garymm/custom-thrust
cd examples
bazel build -s //thrust:version_test
```

produces:
```
➜ bazel build -s //thrust:version_test
SUBCOMMAND: # //thrust:version_test_cu [action 'Compiling thrust/version_test.cu', configuration: c92f7800966ee88d4403d82e9237650892518949abe87c60f2a9a688842ef3b8, execution platform: @local_config_platform//:host]
(cd /home/garymm/.cache/bazel/_bazel_garymm/40b8e895884343ff3f99cfc29b0e57bd/execroot/rules_cuda_examples && \
exec env - \
PATH=/usr/bin \
/usr/local/cuda/bin/nvcc -x cu -Xcompiler -fPIC -ccbin /usr/bin/gcc -I . -I bazel-out/k8-fastbuild/bin -I external/thrust -I bazel-out/k8-fastbuild/bin/external/thrust -I external/cub -I bazel-out/k8-fastbuild/bin/external/cub -I external/local_cuda -I bazel-out/k8-fastbuild/bin/external/local_cuda -isystem external/thrust -isystem bazel-out/k8-fastbuild/bin/external/thrust -isystem external/cub -isystem bazel-out/k8-fastbuild/bin/external/cub -isystem external/local_cuda/cuda/include -isystem bazel-out/k8-fastbuild/bin/external/local_cuda/cuda/include -Xcompiler -g1 -c thrust/version_test.cu -o bazel-out/k8-fastbuild/bin/thrust/_objs/version_test_cu/version_test.pic.o --expt-relaxed-constexpr --expt-extended-lambda)
# Configuration: c92f7800966ee88d4403d82e9237650892518949abe87c60f2a9a688842ef3b8
# Execution platform: @local_config_platform//:host
ERROR: /home/garymm/src/bazel-contrib/rules_cuda/examples/thrust/BUILD.bazel:17:13: Compiling thrust/version_test.cu failed: (Exit 2): nvcc failed: error executing command (from target //thrust:version_test_cu) /usr/local/cuda/bin/nvcc -x cu -Xcompiler -fPIC -ccbin /usr/bin/gcc -I . -I bazel-out/k8-fastbuild/bin -I external/thrust -I bazel-out/k8-fastbuild/bin/external/thrust -I external/cub -I ... (remaining 25 arguments skipped)

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
thrust/version_test.cu(4): error: static assertion failed
static_assert((200001 / 100 % 1000) == 1);```
```

This is on Ubuntu, with CUDA 12.1 installed here:

```
➜ ls /usr/local/cuda*
/usr/local/cuda@ /usr/local/cuda-12@

/usr/local/cuda-12.1
```

Reproduce the failure from the issue in the examples directory with `bazel build -s //thrust:version_test` on the `garymm/custom-thrust` branch. Start with examples/thrust/BUILD.bazel, thrust/version_test.cu, and the emitted nvcc command, then determine why the custom Thrust include is not selected. Done means the version test builds successfully and its static assertion passes.

Written by the indexing model from the issue text.