fix(ci): stop purging powershell via apt on Ubuntu 26.04 (#452)

The Ubuntu 26.04 runner image installs pwsh from a GitHub release
tarball into /opt/microsoft/powershell/7, because the Microsoft apt
repo has no 26.04 build yet. There is no powershell apt package, so
apt-get purge aborted with exit code 100 and every Linux job failed
before the build started.

Drop the entry from the purge list and remove the tarball directory
alongside the other rm -rf cleanups to keep reclaiming that space.

Signed-off-by: Marc Nuri <marc@marcnuri.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: manusa

.github/actions/free-disk-space/action.yml

@@ -16,7 +16,6 @@ runs:
           'mono-.*' \
           'libmono.*' \
           'azure-cli' \
-          'powershell' \
           '^llvm-.*' \
           '^clang-.*'
         sudo apt-get autoremove -y
@@ -25,4 +24,6 @@ runs:
         sudo rm -rf /usr/local/lib/android 2>/dev/null || true
         # Remove .NET
         sudo rm -rf /usr/share/dotnet 2>/dev/null || true
+        # Remove PowerShell (tarball install on Ubuntu 26.04, no apt package)
+        sudo rm -rf /opt/microsoft/powershell 2>/dev/null || true
         df -h