Become when slurping django secret key from file

When using the Funkwhale ansible role for installation for the first time, I found that the playbook failed when trying to slurp the django secret key from the file created in an earlier task, because the file was created as a superuser with mode 600 and the slurp task did not have superuser permissions. The target was Raspberry Pi OS, 32-bit, the September 2022 release based on Debian Buster.

As a workaround I did a temporary, manual chmod on the django secret key file, but this should not be a normal part of install using the Ansible role.