[ci] Install distlib on all macOS versions (#4308)

Failing on macOS-14 now

https://github.com/canonical/multipass/actions/runs/16967777225/job/48096393820?pr=4294

Author: sharder996

.github/workflows/windows-macos.yml

@@ -148,6 +148,11 @@ jobs:
           python \
           wget
 
+    - name: Install dependencies from pip
+      if: ${{ runner.os == 'macOS' }}
+      run: |
+        ${ARCH_WRAPPER} python3 -m pip install --user --upgrade distlib
+
     - name: Install specific QEMU from Choco
       if: ${{ runner.os == 'Windows' }}
       uses: crazy-max/ghaction-chocolatey@v3