fix(updates): notify before installing downloaded updates (#5105)

* fix(windows update): prevent sudden restart

Microsoft has documented that the `NoAutoRebootWithLoggedOnUsers` registry
key is unreliable and does not work as described in newer versions of Windows.

To effectively prevent unexpected restarts in modern configurations,
this PR updates the `Recommended` settings workflow on the `Updates` tab.

Changes
- Modify `AUOptions` to 3: automatic download and manual installation.
- Remove the obsolete registry key.
- Keep the removal of the registry key in functions that reset Windows Update to default.
- Update UI text and documentation.
- Update Pester tests.

Microsoft documentation:
https://learn.microsoft.com/en-us/windows/deployment/update/waas-restart

Resolves #5093

* Clarify update installation notification behavior

---------

Co-authored-by: Chris Titus <contact@christitus.com>

docs/src/content/docs/guides/updates.mdx

@@ -27,7 +27,7 @@ Changing modes adjusts system-wide Windows Update behavior. After switching mode
 - **Feature updates**: Delayed by **365 days** to reduce the chance of disruption from major Windows changes.
 - **Quality updates**: Delayed by **4 days** to allow time for early issues to surface while still keeping the system protected.
 - **Drivers**: Excluded from Windows quality updates.
-- **Restarts**: Scheduled updates do not automatically restart Windows while a user is signed in. A restart explicitly scheduled by a user still takes precedence.
+- **Installation**: Updates download automatically and notify you when they are ready to install. This setting does not control restarts after installation.
 - **Availability**: Update deferral policies apply to Windows Pro, Enterprise, and Education editions.
 - **Why use it**: This mode offers the best balance between security and stability, which is why it is the recommended option for most PCs.