Include potentially distro-specific tasks at runtime

This avoids Ansible trying to ensure `community.general.pacman` is
available, even if that module will never run (because `when` says so).

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2228

roles/custom/matrix-base/tasks/util/ensure_fuse_installed_debian.yml

@@ -0,0 +1,6 @@
+---
+
+- name: Ensure fuse installed (Debian/Raspbian)
+  ansible.builtin.apt:
+    name: fuse
+    state: present