Fix callable type hint in v2

[YunchuWang]

Azure/azure-functions-python-worker#1161

[codecov]

Codecov Report

Merging #160 (c3cd1e9) into dev (3d6797a) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##              dev     #160      +/-   ##
==========================================
+ Coverage   90.08%   90.10%   +0.01%     
==========================================
  Files          51       51              
  Lines        3006     3000       -6     
  Branches      799      796       -3     
==========================================
- Hits         2708     2703       -5     
+ Misses        221      220       -1     
  Partials       77       77              

Flag	Coverage Δ
unittests	90.06% <100.00%> (+0.01%)	⬆️

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

Impacted Files	Coverage Δ
azure/functions/_abc.py	75.76% <ø> (-0.16%)	⬇️
azure/functions/_http_asgi.py	90.42% <100.00%> (ø)
azure/functions/decorators/function_app.py	99.44% <100.00%> (ø)
azure/functions/decorators/utils.py	97.46% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[baluyotraf]

Let me give this a test to see if pyright will accept the hints.