cmd: fix not showing arguments for commands without META-URL

[SandyXSD]

close #2151

[codecov-commenter]

Codecov Report

Merging #2158 (3c9760a) into main (0205399) will decrease coverage by 0.00%.
The diff coverage is 80.00%.

@@            Coverage Diff             @@
##             main    #2158      +/-   ##
==========================================
- Coverage   61.71%   61.71%   -0.01%     
==========================================
  Files         137      137              
  Lines       25022    24895     -127     
==========================================
- Hits        15443    15364      -79     
+ Misses       7772     7746      -26     
+ Partials     1807     1785      -22     

Impacted Files	Coverage Δ
cmd/mdtest.go	29.37% <0.00%> (-0.19%)	⬇️
cmd/dump.go	78.04% <100.00%> (ø)
cmd/gateway.go	87.40% <100.00%> (ø)
cmd/load.go	75.00% <100.00%> (ø)
cmd/main.go	48.10% <100.00%> (+0.28%)	⬆️
pkg/meta/tkv.go	76.57% <0.00%> (-0.23%)	⬇️
pkg/meta/redis.go	71.23% <0.00%> (-0.18%)	⬇️
pkg/chunk/disk_cache.go	80.33% <0.00%> (ø)
pkg/meta/sql.go	65.38% <0.00%> (+0.02%)	⬆️
pkg/chunk/cached_store.go	76.37% <0.00%> (+0.18%)	⬆️
... and 3 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0205399...3c9760a. Read the comment docs.