Fix issue with ctx var resetting

[uriyyo]

Fixes #309

[codecov]

Codecov Report

Merging #310 (804f26f) into main (02c2de9) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #310   +/-   ##
=======================================
  Coverage   99.40%   99.40%           
=======================================
  Files          26       26           
  Lines         502      503    +1     
=======================================
+ Hits          499      500    +1     
  Misses          3        3           

Impacted Files	Coverage Δ
fastapi_pagination/api.py	100.00% <100.00%> (ø)

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