It was becoming a real PITA to have to look in the environments.js to see which constant was used then hop back to the constants file to see what the actual URL was. Since those constants were never used anywhere else, and we don't _want_ them used anywhere else (the code should get endpoints from the subscription/environment), having them as named constants in a separate file wasn't adding any value.

Consider it an inlining refactoring. It's still once-and-only-once, so we're still doing the right thing as far as managing these data items is concerned.