You can definitely use that, and since it's a solid 60A circuit, the Tesla UMC, which can only draw 32A maximum, will have no issues at all. The trick is to get access to just one phase of the three phase connections.
Suggestion 1, build your own, as
@qdeathstar was suggesting. I've built a pigtail adapter of a smaller type, and it's not hard, but you do want to get the connections really tight.
Suggestion 2, if you don't trust yourself to build one of these, as a lot of people might not...
Contact
EVSE Adapters – Electric vehicle charging solutions, adapter cords for EV, RV, welders, and more. Charge anywhere.
They offer a lot of kinds of charging adapters, and they will custom make some too. So you could contact them and tell them you want a pigtail adapter from the 15-60, using only one phase to a 6-50 receptacle, and they can probably make that, and it will be a good solidly built one that is nice and reliable.