Truncate long Advanced Preferences entries with ellipses

This truncates long Advanced Preferences list entry labels and values
with ellipses using hardcoded character count limits in order to avoid
stretching out the listbox too much over the dialog's width.

Currently, this is notably necessary for the German translation.

The character count limits chosen for this commit (46 for the label, 8
for the value) only really work with the basic ASCII character set. Some
Unicode characters may be rendered wider. Furthermore, the Preferences
page selection list may container longer entries that push this listbox
further to the right, closer to the dialog's right edge.

Also, I really hope most languages have words for 'yes' or 'no' that are
at most 8 characters in length or can at least be read without ambiguity
when truncated to that limit. At least none of the translations we
support which have translated those words hit the limit.
Shorten label for the savegame version prompt advanced preferences entry