Fix bug with report not appearing

[stavros11]

The report (index.html) is not properly rendered after a run is finished. This PR should fix this issue.

Checklist:

• Reviewers confirm new code works as expected.
• Tests are passing.
• Coverage does not decrease.
• Documentation is updated.

[codecov]

Codecov Report

Merging #199 (f157bef) into main (e74a842) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #199   +/-   ##
=======================================
  Coverage   36.07%   36.07%           
=======================================
  Files          19       19           
  Lines        1192     1192           
=======================================
  Hits          430      430           
  Misses        762      762           

Flag	Coverage Δ
unittests	36.07% <ø> (ø)

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

Impacted Files	Coverage Δ
src/qibocal/web/report.py	0.00% <ø> (ø)

[andrea-pasquale]

Thanks @stavros11.
It works for me.