Guardrails to ensure we dont run target LV out of space; minor tweaks

tasks/capture_lv_device_details.yml

@@ -109,7 +109,7 @@
     - name: Assert if we need to shrink the logical volume to gain PE
       ansible.builtin.assert:
         that: (bigboot_lv_pe_size_in_mb[:-3] | int) >= (bigboot_expansion_diff_mb[:-3] | int)
-        fail_msg: Not enough PE to expand /boot.
+        fail_msg: Not enough PE to expand /boot. Will need to shrink target LV.
 
   rescue:
     - name: Set flag for Shrink_LV execution