I've seen this maybe three times over the decades since about 1970 but it seems, from the animation type, to be many years older
What I remember:
Black and white, four minutes or so. It starts off with a little cartoon reindeer fourth-walling it at the viewer, then some music starts (NOT jingle bells, possibly Sleigh Ride) and it does a dance. This takes place under a starry sky in what is presumably Santa's Village.
As it dances an elf or two come outside and join in, then another reindeer, then more "not remembers"
Santa appears but he's not the Coca Cola version, he has black hair and beard...he slightly resembles Bluto from Popeye the Sailor. He gives a big hearty laugh and then he turns to the fourth wall and repeats the laugh.
The music continues and all are dancing with the little reindeer in the centre, the cartoon fades away with Santa again laughing.
Note: previously asked on SFF Chronicles and further questions were raised...
Update: Dear all , please keep a special eye out on TV over this holiday period, one of us might get lucky and spot it!
Merry Christmas from Danny