The per-core pre-release switch and its label sit in a horizontal
StackPanel inside a fixed-width column of the update dialog.
Translations longer than the column do not fit: in Avalonia the label
runs over the core name and the update status (Russian, French,
Hungarian, Persian), and in WPF it is cut off. Use a DockPanel so that
the label wraps inside its column, as the interval label of the
subscription window does since #10292. The dialog keeps its width.
In Avalonia the panel also had a vertical margin on top of the
margin of the switch, so the two rows with the switch were 8 px taller
than the other rows. Use a horizontal-only margin, as the WPF view
already does.