fix(ci): update symlink creation command in GitHub Actions workflow for Windows

- Replaced PowerShell commands with native CMD commands for creating a directory and symlink, improving compatibility and simplicity.
- Ensured the directory is created only if it does not already exist, enhancing the robustness of the workflow.

.github/workflows/core_tests.yml

@@ -45,8 +45,10 @@ jobs:
 
       - name: Symlink target to C:\
         if: ${{ matrix.settings.os == 'windows' }}
+        shell: cmd
         run: |
-          powershell -ExecutionPolicy Bypass -Command "New-Item -ItemType Directory -Force -Path C:\spacedrive_target; New-Item -Path target -ItemType Junction -Value C:\spacedrive_target"
+          if not exist C:\spacedrive_target mkdir C:\spacedrive_target
+          mklink /J target C:\spacedrive_target
 
       - name: Checkout repository
         uses: actions/checkout@v4