cli/object: Fix missing RPC endpoint that is set through config file

Previously, object command that opened dynamic session with storage node
(like `put`) failed with `can't fetch current epoch: can't parse RPC
endpoint: missing port in address` error when RPC endpoint was set in
the config file and omitted in flags.

Get network endpoint from viper box which contains values from config
file.

Refs #1574.

Signed-off-by: Leonard Lyubich <[email protected]>

CHANGELOG.md

@@ -15,6 +15,7 @@ Changelog for NeoFS Node
 - Synchronous objects `PUT` to the local storage (#2607)
 - `copies_number` field was not used in `PUT` request handling (#2607)
 - Neo-go notary deposit data workaround (#2429)
+- Error of missing network endpoint in `neofs-cli object` commands when it is set in the file config (#2608)
 
 ### Changed
 - FSTree storage now uses more efficient and safe temporary files under Linux (#2566)

cmd/neofs-cli/modules/object/util.go

@@ -278,8 +278,7 @@ func OpenSessionViaClient(ctx context.Context, cmd *cobra.Command, dst SessionPr
 	const sessionLifetime = 10 // in NeoFS epochs
 
 	common.PrintVerbose(cmd, "Opening remote session with the node...")
-	endpoint, _ := cmd.Flags().GetString(commonflags.RPC)
-	currEpoch, err := internal.GetCurrentEpoch(ctx, endpoint)
+	currEpoch, err := internal.GetCurrentEpoch(ctx, viper.GetString(commonflags.RPC))
 	common.ExitOnErr(cmd, "can't fetch current epoch: %w", err)
 	exp := currEpoch + sessionLifetime
 	err = sessionCli.CreateSession(ctx, &tok, cli, *key, exp, currEpoch)