Fix AIO_STATIC_PATH env variable name in runserver command help

[Cycloctane]

What do these changes do?

This pr fixes a typo in runserver command's --help.

Are there changes in behavior for the user?

Related issue number

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.78%. Comparing base (a44adf5) to head (1b5e62c).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #706   +/-   ##
=======================================
  Coverage   95.78%   95.78%           
=======================================
  Files          23       23           
  Lines        1686     1686           
  Branches      194      194           
=======================================
  Hits         1615     1615           
  Misses         46       46           
  Partials       25       25           

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