Don't close Tails Cloner after clicking OK on 'Installation Complete' pop-up
Based on !1302 (merged)
Closes #19696 (closed).
As desired by @sajolida the 'Close' button was changed to 'OK' and clicking it only closes the 'Installation Complete' pop-up not the entire Tails Cloner.
It does not reset Tails Cloner, so cloning a new device will still require closing and restarting it but this makes it easier to read the dialog afterwards and doesn't unexpectedly kill the whole window.