remove useless err return value

[ucwong]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 47.22%. Comparing base (c2be31f) to head (5900818).
Report is 35 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1954      +/-   ##
==========================================
- Coverage   47.25%   47.22%   -0.03%     
==========================================
  Files         568      568              
  Lines       68849    68845       -4     
==========================================
- Hits        32534    32514      -20     
- Misses      33789    33808      +19     
+ Partials     2526     2523       -3     

Files	Coverage Δ
ctxc/tracers/api.go	0.41% <0.00%> (+<0.01%)	⬆️
internal/ctxcapi/api.go	8.65% <0.00%> (+0.01%)	⬆️

... and 11 files with indirect coverage changes