feat(convert_compiler_to_legacy): update internal compiler pool address retrieval

- Changed retrieval of `internal_compiler_a_pool_address` and `internal_compiler_b_pool_address` to use `getvar` function.
- Ensured compatibility with updated cluster parameter structure.

This update improves the robustness of the plan by ensuring correct retrieval of internal compiler pool addresses.

Author: CoMfUcIoS

plans/convert_compiler_to_legacy.pp

@@ -26,8 +26,8 @@
         undef   => $primary_target,
         default => $primary_target.peadm::certname(),
       },
-      internal_compiler_a_pool_address => $cluster['params']['internal_compiler_a_pool_address'],
-      internal_compiler_b_pool_address => $cluster['params']['internal_compiler_b_pool_address'],
+      internal_compiler_a_pool_address => getvar('cluster.params.internal_compiler_a_pool_address'),
+      internal_compiler_b_pool_address => getvar('cluster.params.internal_compiler_b_pool_address'),
       require                          => Class['peadm::setup::node_manager_yaml'],
     }
   }