lib: Fix name reordering to handle commas without spaces

lib: Fix name reordering to handle commas without spaces

Notmuch automatically re-orders names of the format "Last, First" to
"First Last" when the associated email address is
First.Last@example.com. But, if a name is of the format "Last,First"
then notmuch will format the name as "irst Last". Handle any number of
spaces after the comma, including none.