Cannot copy text from About window with ⌘C

### Prerequisites

- [x] I have checked the existing issues for duplicates
- [x] I am reporting a bug, not a feature request

### Description

The text displayed in AdGuard Mini's About window cannot be copied using the standard macOS `⌘C` keyboard shortcut.

For example, the version information shown in the About window:

> AdGuard Mini
> Version 2.3.0 (1091)

cannot be selected/copied with `⌘C`.

This is particularly inconvenient when reporting issues, since users may need to manually type the AdGuard Mini version/build number or right-click copy instead of being able to copy it directly from the About window.

### Steps to reproduce

1. Open AdGuard Mini.
2. Open **About**.
3. Try to select the displayed version information.
4. Press `⌘C`.

### Expected behavior

Text displayed in the About window should be selectable and copyable using the standard macOS text-selection and `⌘C` keyboard shortcut.

At minimum, the version/build number should provide a way to copy it to the clipboard.

### Actual behavior

The text in the About window cannot be copied using `⌘C`.

### Environment

- AdGuard Mini for Mac: `2.3.0 (1091)`
- macOS: `27.0 Beta`
- macOS build: `26A5406e`

### Screenshot

Unable to capture.

### Additional information

I am not sure whether this is an intentional design choice or an issue with the text controls used by the About window.

If the text is intentionally non-selectable, it would still be useful to provide a dedicated way to copy the version/build information, particularly because this information is frequently needed when submitting bug reports.

If macOS shortcuts aren't generally supported at all, it would be good to enable the use of shortcuts throughout the entire app.