[#1442] cli/tree: Allow to specify rpc-endpoint with config file

We have several ways to specify the `rpc-endpoint`: with a flag,
with a single config file or multiple files. Before, the `rpc-endpoint`
flag was marked as required. Because `cobra` checked the required flag
presence first, it prevented specifying `rpc-endpoint` with a config file.

Signed-off-by: Aleksey Savchuk <a.savchuk@yadro.com>

cmd/frostfs-cli/modules/tree/add_by_path.go

@@ -36,7 +36,6 @@ func initAddByPathCmd() {
 	ff.String(pathFlagKey, "", "Path to a node")
 	ff.StringSlice(metaFlagKey, nil, "Meta pairs in the form of Key1=[0x]Value1,Key2=[0x]Value2")
 
-	_ = cobra.MarkFlagRequired(ff, commonflags.RPC)
 	_ = cobra.MarkFlagRequired(ff, pathFlagKey)
 }