style: don't compare var value with empty string

tasks/configure_swap.yml

@@ -9,7 +9,7 @@
   ansible.builtin.command: swapoff -va
   when:
     - ansible_hostname is not search("validate")
-    - swap_active.stdout == ""
+    - swap_active.stdout | length == 0
   register: disable_swap
   changed_when: disable_swap.stdout not in "swapoff LABEL=swap"
 
@@ -20,4 +20,4 @@
     state: "absent"
   when:
     - ansible_hostname is not search("validate")
-    - swap_active.stdout == ""
+    - swap_active.stdout | length == 0