feat: on low wasm memory hook

spec/_attachments/ic.did

@@ -15,6 +15,7 @@ type canister_settings = record {
     reserved_cycles_limit : opt nat;
     log_visibility : opt log_visibility;
     wasm_memory_limit : opt nat;
+    wasm_memory_threshold : opt nat;
 };
 
 type definite_canister_settings = record {
@@ -25,6 +26,7 @@ type definite_canister_settings = record {
     reserved_cycles_limit : nat;
     log_visibility : log_visibility;
     wasm_memory_limit : nat;
+    wasm_memory_threshold: nat;
 };
 
 type change_origin = variant {