Select database on key selection in Magickeyboard

**Is your feature request related to a problem? Please describe.**
I would not say that this is a bug, this is an improvement

**Describe the solution you'd like**
In the key selection dialog in Magickeyboard, it is impossible to select another database.
I have two databases. One work base is another personal. My personal database is marked with an asterisk, so on the site when you select a key using Magickeyboard, it opens first. But this is not always necessary. I've tried pressing the back button (on top), but this action just closes KeePassDX Pro. Therefore, in order for me to select the desired key, I first need to open KeePassDX, select another database, unlock it, then open the site I need and select the desired key using Magickeyboard. I hope I clearly explained))

**Describe alternatives you've considered**
The back button at the top should take you to the database selection window.

**Additional context**
I do not have it

Start by tracing the Magickeyboard key selection dialog and its top back-button handling. Confirm how the dialog currently opens and why back closes KeePassDX Pro; done means back reaches database selection, lets the user choose another database, and then select a key.

Written by the indexing model from the issue text.