[#768] adm: Do not change frostfsid admin on update

Behave similarly to the netmap contract.
Close #768

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

cmd/frostfs-adm/internal/modules/morph/initialize_deploy.go

@@ -550,7 +550,17 @@ func (c *initializeContext) getContractDeployData(ctrName string, keysParam []an
 			nnsCs.Hash,
 			"container")
 	case frostfsIDContract:
-		h, found, err := getFrostfsIDAdmin(viper.GetViper())
+		var (
+			h     util.Uint160
+			found bool
+			err   error
+		)
+		if method == updateMethodName {
+			h, found, err = c.getFrostfsIDAdminFromContract()
+		}
+		if method != updateMethodName || err == nil && !found {
+			h, found, err = getFrostfsIDAdmin(viper.GetViper())
+		}
 		if err != nil {
 			return nil, err
 		}
@@ -588,6 +598,35 @@ func (c *initializeContext) getContractDeployData(ctrName string, keysParam []an
 	return items, nil
 }
 
+func (c *initializeContext) getFrostfsIDAdminFromContract() (util.Uint160, bool, error) {
+	r := management.NewReader(c.ReadOnlyInvoker)
+	cs, err := r.GetContractByID(1)
+	if err != nil {
+		return util.Uint160{}, false, fmt.Errorf("get nns contract: %w", err)
+	}
+	fidHash, err := nnsResolveHash(c.ReadOnlyInvoker, cs.Hash, domainOf(frostfsIDContract))
+	if err != nil {
+		return util.Uint160{}, false, fmt.Errorf("resolve frostfsid contract hash: %w", err)
+	}
+	item, err := unwrap.Item(c.ReadOnlyInvoker.Call(fidHash, "getAdmin"))
+	if err != nil {
+		return util.Uint160{}, false, fmt.Errorf("getAdmin: %w", err)
+	}
+	if _, ok := item.(stackitem.Null); ok {
+		return util.Uint160{}, false, nil
+	}
+
+	bs, err := item.TryBytes()
+	if err != nil {
+		return util.Uint160{}, true, fmt.Errorf("getAdmin: decode result: %w", err)
+	}
+	h, err := util.Uint160DecodeBytesBE(bs)
+	if err != nil {
+		return util.Uint160{}, true, fmt.Errorf("getAdmin: decode result: %w", err)
+	}
+	return h, true, nil
+}
+
 func (c *initializeContext) getNetConfigFromNetmapContract() ([]stackitem.Item, error) {
 	r := management.NewReader(c.ReadOnlyInvoker)
 	cs, err := r.GetContractByID(1)