Fix variable references

tasks/capture_boot_device_details.yml

@@ -27,7 +27,7 @@
 
 - name: Set bigboot size 4k aligned
   ansible.builtin.set_fact:
-    bigboot_partition_size: "{{ bigboot_size_expansion_mb[:-2] | int | get_block_size_up }}"
+    bigboot_size: "{{ bigboot_size_expansion_mb[:-2] | int | get_block_size_up }}"
 
 - name: Validate if we need to expand boot
   block:
@@ -48,4 +48,4 @@
 
     - name: Expansion of /boot required
       ansible.builtin.debug:
-        msg: "Will need to expand /boot by an additional {{ bigboot_partition_size }}."
+        msg: "Will need to expand /boot by an additional {{ bigboot_size }}."