Pin Azure CLI to 2.90.0 and retry access denied errors in the installer

[ramonsmits]

Most CI runs since 2026-10-16 fail in the Azure jobs, independent of the change under test. The cause is in CI infrastructure, not in the code the jobs test.

Azure jobs: Azure CLI deadlocks while it creates the Service Bus namespace. Azure CLI 2.91.0 runs on Python 3.14 and hits the import deadlock reported in Azure/azure-cli#33996 during long-running operations, on Linux and on Windows. The fix (Azure/azure-cli#34201) merged on 2026-10-12 and is not in 2.91.0, which is still the latest release. The composite action that upgraded the CLI to the latest version now installs 2.90.0: the .deb from the Microsoft package repository on Linux, the ZIP distribution on Windows, because the MSI refuses to install over the newer version on the runner image. The action carries a comment with the condition to restore the upgrade.

Installer: retry UnauthorizedAccessException when it deletes a directory. Windows reports a file that a process still holds, or that an antivirus scanner holds, as UnauthorizedAccessException, for example right after the process that loaded it exits. FileUtils.RunWithRetries only retried IOException, so a delete during an uninstall failed on the first attempt. This is what made PackagedRavenDBTests fail on Windows-DefaultCore until #5969 gave the test its own cleanup retry. The test no longer uses FileUtils, so this change is a hardening of the installer only.

Not addressed: Windows-IBMMQ and other WSL jobs cancelled after 30 minutes. The Setup WSL step hangs and the runner ignores the step timeout. The cause is in Particular/setup-wsl-action, where a diagnostics change is in review.

[rbev]

There is an issue open on the runner images for the WSL hang actions/runner-images#14938