[#1186] cli: Make owner field optional for bearer token

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

cmd/frostfs-cli/modules/bearer/create.go

@@ -67,7 +67,6 @@ func init() {
 	_ = cobra.MarkFlagFilename(createCmd.Flags(), apeFlag)
 
 	_ = cobra.MarkFlagRequired(createCmd.Flags(), commonflags.ExpireAt)
-	_ = cobra.MarkFlagRequired(createCmd.Flags(), ownerFlag)
 	_ = cobra.MarkFlagRequired(createCmd.Flags(), outFlag)
 }
 
@@ -108,16 +107,16 @@ func createToken(cmd *cobra.Command, _ []string) {
 			fmt.Errorf("expiration epoch is less than not-valid-before epoch: %d < %d", exp, nvb))
 	}
 
-	ownerStr, _ := cmd.Flags().GetString(ownerFlag)
-
-	var ownerID user.ID
-	commonCmd.ExitOnErr(cmd, "can't parse recipient: %w", ownerID.DecodeString(ownerStr))
-
 	var b bearer.Token
 	b.SetExp(exp)
 	b.SetNbf(nvb)
 	b.SetIat(iat)
-	b.ForUser(ownerID)
+
+	if ownerStr, _ := cmd.Flags().GetString(ownerFlag); ownerStr != "" {
+		var ownerID user.ID
+		commonCmd.ExitOnErr(cmd, "can't parse recipient: %w", ownerID.DecodeString(ownerStr))
+		b.ForUser(ownerID)
+	}
 
 	impersonate, _ := cmd.Flags().GetBool(impersonateFlag)
 	b.SetImpersonate(impersonate)