fix: check the existence of the tag before updating pull time

[chlins]

Check tag before update pull time, there are two purposes:

1. avoid noise log in the caller.("failed to update pull time, tag 0 not found")
2. reduce the db connection because GetTag needs query tag from db.

Signed-off-by: chlins chenyuzh@vmware.com

[codecov]

Codecov Report

Merging #16510 (4f2cd93) into main (6673841) will decrease coverage by 0.00%.
The diff coverage is 84.61%.

@@            Coverage Diff             @@
##             main   #16510      +/-   ##
==========================================
- Coverage   67.43%   67.43%   -0.01%     
==========================================
  Files         949      949              
  Lines       78812    78814       +2     
  Branches     2321     2321              
==========================================
+ Hits        53149    53150       +1     
- Misses      22112    22114       +2     
+ Partials     3551     3550       -1     

Flag	Coverage Δ
unittests	67.43% <84.61%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/controller/artifact/controller.go	64.93% <84.61%> (+0.22%)	⬆️
...g-retention-tasks/tag-retention-tasks.component.ts	60.00% <0.00%> (-25.72%)	⬇️
src/common/rbac/system/namespace.go	33.33% <0.00%> (-11.12%)	⬇️
src/jobservice/worker/cworker/c_worker.go	68.42% <0.00%> (+1.91%)	⬆️
...-nav/gc-page/gc/gc-history/gc-history.component.ts	60.37% <0.00%> (+9.43%)	⬆️

[wy65701436]

lgtm