Remove old cvmfs api repo on modern ubuntu

Fixes
```
root@gat-1:/etc/apt# apt update
E: Conflicting values set for option ALLOW_INSECURE regarding source <set> <unset>
E: The list of sources could not be read.
```

Author: mvdbeek

tasks/init_debian.yml

@@ -33,6 +33,13 @@
     repo: deb [allow-insecure=true] https://cvmrepo.web.cern.ch/cvmrepo/apt/ {{ ansible_distribution_release }}-prod main
   when: ansible_distribution == 'Ubuntu' and ansible_distribution_release in ('bionic', 'xenial', 'precise', 'focal')
 
+- name: Remove old CernVM apt repository (legacy format)
+  ansible.builtin.apt_repository:
+    filename: cernvm.list
+    repo: deb [allow-insecure=true] https://cvmrepo.web.cern.ch/cvmrepo/apt/ {{ ansible_distribution_release }}-prod main
+    state: absent
+  when: ansible_distribution == 'Ubuntu' and ansible_distribution_release in ('jammy', 'noble')
+
 - name: Configure CernVM apt repository for modern Ubuntu releases
   ansible.builtin.apt_repository:
     filename: cernvm