Because of the ordering of assignments in ChannelSettingsDialog's ctor,
we weren't assigning the global config before passing it in to the
list modes pane. This caused NPEs if toggling the 'show extended info'
option and saving.

Change-Id: I89f1ca9e29aa38fcf278e9afd2b9fbc214b4fbe3
Fixes-Issue: CLIENT-454
Reviewed-on: http://gerrit.dmdirc.com/3212
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager