[Docs] Update setupFilesAfterEnv usage example

[szhigunov]

According to Jest documentation, https://jestjs.io/docs/en/configuration#setupfilesafterenv-array is now of type array.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.14%. Comparing base (c5d5ee7) to head (b1e9658).
⚠️ Report is 159 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2414   +/-   ##
=======================================
  Coverage   96.14%   96.14%           
=======================================
  Files          49       49           
  Lines        3835     3835           
  Branches     1072     1072           
=======================================
  Hits         3687     3687           
  Misses        148      148           

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