Fix issue in getting current request through classmethod when served through a different ASGI server

[Thirumalai]

fixes #2759

[codecov]

Codecov Report

Patch coverage: 100.000% and project coverage change: +0.001 🎉

Comparison is base (af67801) 88.938% compared to head (59b164f) 88.940%.

❗ Current head 59b164f differs from pull request most recent head 77e626f. Consider uploading reports for the commit 77e626f to get more accurate results

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #2760       +/-   ##
=============================================
+ Coverage   88.938%   88.940%   +0.001%     
=============================================
  Files           92        92               
  Lines         6952      6953        +1     
  Branches      1185      1185               
=============================================
+ Hits          6183      6184        +1     
  Misses         527       527               
  Partials       242       242               

Impacted Files	Coverage Δ
sanic/asgi.py	91.729% <100.000%> (+0.062%)	⬆️

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