You are right, it was a dependency for long time. But when you update the package a popup shows up and you have to agree to 3rd party licenses if you want to continue installation… And Xceed license obliges to pay for it.
We read in UiPath Master Software and Services Agreement:
4.3. Third-Party Licenses. Technology may contain or may be used with third party components, including open-source software, which are the property of their respective owners. Notwithstanding anything to the contrary herein, use of the open-source software will be subject to the license terms and conditions applicable to such open-source software, to the extent required by the applicable licensor (which terms shall not restrict the license rights granted to Customer hereunder).