Chris Willman Senior Music Writer and Chief Music Critic The word “contested” shows up a lot lately in singer-songwriter Elizabeth Chan’s world, as she made headlines this summer for going to court to try to ensure that Mariah Carey is not legally granted sole possession of the “Queen of Christmas” tag, which has also been applied to her. But there’s at least one aspect of what Chan does that will likely continue to go unchallenged. With her 12th album, “12 Months of Christmas,” coming out this week, Chan further breaks her own record for having the most all-original Christmas albums in circulation of any nationally established pop artist. Although “most Christmas albums” is not the sort of record where Santa is keeping an official list and checking it twice — nor the Guinness Book, for that matter — it seems safe to say that no one else is even close when it comes to self-penned, all-new Yuletide collections, thanks to the one-a-year pace established by Chan, the only nationally recognized artist who does nothing but Christmas albums.