fix(types): fix types of flat configs

[CHC383]

Fixes #3878

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 97.80%. Comparing base (e6b5b41) to head (2236728). Report is 13 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3879      +/-   ##
==========================================
+ Coverage   97.66%   97.80%   +0.14%     
==========================================
  Files         136      136              
  Lines        9978     9978              
  Branches     3703     3703              
==========================================
+ Hits         9745     9759      +14     
+ Misses        233      219      -14     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• :package: JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.