[frontend] Fix file indexing accessing to external file (#6943)

[Kedae]

Closes #6943

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.55%. Comparing base (eafd91a) to head (f64697a).
Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7254   +/-   ##
=======================================
  Coverage   67.55%   67.55%           
=======================================
  Files         561      561           
  Lines       68744    68744           
  Branches     5837     5838    +1     
=======================================
  Hits        46437    46437           
  Misses      22307    22307           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.