Bug Report: LVM role conditional evaluates to string instead of boolean

  **Bug Report: LVM role conditional evaluates to string instead of boolean**

  **File:** `ansible/roles/lvm/tasks/manage_lvm.yml`
  **Line:** 10

  **Problem:**
  The `when` condition in the "Rescan LVM Volume Groups" task:
  ```yaml
  when: ((lvm__register_devices_filter | d() and lvm__register_devices_filter is changed) or
         (lvm__register_devices_global_filter | d() and lvm__register_devices_global_filter is changed))

Can fail with:

  Conditional result (False) was derived from value of type 'str'

Root Cause:
When lvm__register_devices_filter is undefined, | d() returns an empty string.
The expression lvm__register_devices_filter | d() and ... evaluates to a string,
not a boolean.

Suggested Fix:

  when: ((lvm__register_devices_filter is defined and lvm__register_devices_filter.changed) or
         (lvm__register_devices_global_filter is defined and lvm__register_devices_global_filter.changed))

Workaround:
Users can pre-define these variables in host_vars:

  lvm__register_devices_filter:
    changed: false
  lvm__register_devices_global_filter:
    changed: false

Environment:

• DebOps version: 3.3.0
• Ansible core: 2.21.2
• Python: 3.12

Start at ansible/roles/lvm/tasks/manage_lvm.yml line 10 and inspect the "Rescan LVM Volume Groups" task and its when condition. Reproduce the case with the LVM filter variables undefined, then verify that the condition evaluates as a boolean and that the task behaves correctly without the host_vars workaround.