Bundle uv in Windows ARM64 builds (#16070)

* fix: include bundled UV binary for arm64

* fix: update unit test CI

* Install unit-test numpy only with the bundled uv

* Simplify the unit-test script's uv lookup

---------

Co-authored-by: SoftFever <103989404+SoftFever@users.noreply.github.com>
Co-authored-by: SoftFever <softfeverever@gmail.com>

.github/workflows/unit_tests.yml

@@ -44,14 +44,6 @@ jobs:
         uses: actions/download-artifact@v8
         with:
           name: ${{ inputs.artifact }}
-      # run_unit_tests.sh installs the plugin tests' numpy with the uv the build stages
-      # beside them; the Windows arm64 build bundles none, so put one on PATH there.
-      - name: Install uv
-        if: runner.os == 'Windows' && runner.arch == 'ARM64'
-        uses: astral-sh/setup-uv@v10.2.0
-        with:
-          version: "0.11.21"  # ORCA_UV_VERSION in CMakeLists.txt
-          enable-cache: false
       - uses: lukka/get-cmake@latest
         with:
           cmakeVersion: "~4.3.0"  # use most recent 4.3.x version