inhibit: pass arg_json_format_flags to introspect_cli()

All other commands with a --json= option do so, so that --json= governs
the formatting of the introspection output.

Fixes 548c9cd71c.

src/login/inhibit.c

@@ -240,7 +240,7 @@ static int parse_argv(int argc, char *argv[], char ***remaining_args) {
                         break;
 
                 OPTION_COMMON_INTROSPECT_CLI:
-                        return introspect_cli(SD_JSON_FORMAT_OFF);
+                        return introspect_cli(arg_json_format_flags);
                 }
 
         char **args = option_parser_get_args(&opts);