Allow manually downgrading the app

[AlexandrPkhm]

Issue Details

When a user tries to install a build with a lower version number than the currently installed one, the installer displays the message “AdGuard VPN is already installed.” This safeguard exists to avoid migration-related issues.

Currently, the only way to override this behavior is to run the installer from PowerShell using the /F key.

Proposed solution

Allow downgrading by manually running the installer without requiring a special key. Any potential migration issues should be handled by resetting the application settings to their default values during the downgrade process or on first launch.

Additional info

Awating for upwotes

[shamarin]

Good idea, especially when user want to get back from beta or nightly version to stable.