Hi,
I’m not sure if you want to install the team edition (the open source) or just finish the trial and get back the team edition features.
If the last is your case, you can just click on “Remove License and Downgrade Server” and it will downgrade your installation to the Starter plan that has the same features as in the Team Edition.
If you want to revert to the open source edition, following the instructions mentioned on the thread that @amy.blais referred should work!