Add an option to disable saving the last opened tab/menu position on exit

### Issue Details

Currently, in AdGuard 8.0 for Windows, the application automatically saves the last opened tab (menu) upon exit, and restores it on the next launch. There is currently no option in the settings or advanced settings to disable this behavior.

I would like to request an option to disable this feature so that the application can always launch into the default main dashboard screen.

### Proposed solution

* Add a toggle switch in **Settings -> General** or **Advanced Settings** (e.g., `Remember last opened tab`).
* When turned **OFF**, AdGuard should always open to the default Home/Dashboard screen regardless of which menu or tab was active when the app was last closed.

### Why this is needed

For users who prefer a clean and consistent startup experience, having the app open to a specific sub-menu can be disruptive. Providing a toggle gives users more control over the UI behavior.