[MM-56078] mmctl: assume local mode when no credentials found (#26215)

* assume local mode when no credentials found

* Use variable

---------

Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/cmd/mmctl/commands/completion.go

@@ -218,7 +218,7 @@ func validateArgsWithClient(fn validateArgsFn) func(cmd *cobra.Command, args []s
 		ctx, cancel := context.WithTimeout(context.Background(), shellCompleteTimeout)
 		defer cancel()
 
-		c, _, _, err := getClient(ctx)
+		c, _, _, err := getClient(ctx, cmd)
 		if err != nil {
 			return nil, cobra.ShellCompDirectiveError
 		}