[BUG] Moving all user stories from one sprint to another won't close the sprint the user stories were moved from

[RKLBusinessDevelopment]

Describe the bug
When moving user stories/tasks that couldn't be completed in one sprint are moved to a new sprint, the sprint the user stories/tasks were moved from is not closed. As there is no possibility to close a sprint manually, I am now left with an open sprint without any user stories/tasks.

How can we reproduce the behavior
Create two sprints. Add user stories to one sprint. Then move all user stories to a new sprint, so the first sprint has no user stories anymore.

Workarounds
I have successfully used the following workaround: I added a dummy task to the sprint and closed it. Then the sprint was closed too.

Taiga environment
This problem occurs in a self-hosted Taiga instance that has been installed with docker.