fix(registry/consul):fix can't get service instance in async mode

[letian0805]

Description (what this PR does / why we need it):

Which issue(s) this PR fixes (resolves / be part of):

fixes #1727 problem 2

Other special notes for reviewer:

[codecov-commenter]

Codecov Report

Merging #1731 (7a68c3f) into main (11a6120) will increase coverage by 0.09%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1731      +/-   ##
==========================================
+ Coverage   81.17%   81.27%   +0.09%     
==========================================
  Files          78       78              
  Lines        3469     3476       +7     
==========================================
+ Hits         2816     2825       +9     
+ Misses        449      446       -3     
- Partials      204      205       +1     

Impacted Files	Coverage Δ
transport/http/resolver.go	64.00% <0.00%> (-4.00%)	⬇️
transport/grpc/client.go	95.45% <0.00%> (-0.06%)	⬇️
transport/grpc/server.go	93.33% <0.00%> (+1.25%)	⬆️
transport/http/server.go	77.41% <0.00%> (+2.41%)	⬆️
internal/context/context.go	100.00% <0.00%> (+2.98%)	⬆️

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[letian0805]

@longXboy @haiyux