No. Lights of the christmas tree interfering with The Force, not likely.
Well, OK, if all the people in the united states gathered into one state, the gravitational effects of all those bodies in one place would be detectable by the ultra sensitive GRACE satellite system. And, any electronic device that is running, including light bulbs or just wires carrying alternating current, put EMF out into the air, and potentially, this energy could interfere with other EMF energy such as what your wifi uses.
Overall if your house is full of electronic devices that are running, including multiple wireless/bluetooth transmission systems, then you can have interference. But Christmas lights would be a very small contribution.
Christmas trees, however, do attract electronic devices. Don’t believe me? Put out a Christmas tree. On the morning of December 25th, there will be electronic devices, wrapped in festive paper, gathered around the base of the tree. So, in directly, I suppose there could be an effect…
The only reason I’m mentioning this at all is because it seems to be a question being asked this year. Like this:
Part of the War on Christmas, I assume.