fix: Remove extra slash for file url

[aisensiy]

This is the issue: HumanSignal/label-studio-frontend#733

---

I am using label-studio with the --host parameter like this:

$ label-studio --host https://openbayes.com/jobs/abc/proxy/8080

Every thing works good until I import some images for ocr task. It seems that the generated urls in frontend have more than one / between the prefix and the upload path:

If I mannully remove the extra / in the

/jobs/open-tutorials/jobs/proxy/8080 ---->//<---- data/upload/1/df0703be-AAMU4003561_45R1__011_0741_181125_224515_01_Manual_1.jpg

the url can access successfully.

[codecov]

Codecov Report

Merging #2601 (36046e1) into develop (17b40da) will decrease coverage by 0.87%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #2601      +/-   ##
===========================================
- Coverage    77.80%   76.92%   -0.88%     
===========================================
  Files          137      144       +7     
  Lines         9951    10422     +471     
===========================================
+ Hits          7742     8017     +275     
- Misses        2209     2405     +196     

Impacted Files	Coverage Δ
label_studio/label_studio/users/mixins.py	75.00% <0.00%> (-12.50%)	⬇️
...bel_studio/label_studio/organizations/functions.py	66.66% <0.00%> (-10.26%)	⬇️
...l_studio/label_studio/core/templatetags/filters.py	48.75% <0.00%> (-6.20%)	⬇️
.../label_studio/data_manager/actions/experimental.py	15.15% <0.00%> (-4.37%)	⬇️
label_studio/label_studio/users/api.py	80.45% <0.00%> (-3.88%)	⬇️
label_studio/label_studio/ml/serializers.py	92.30% <0.00%> (-2.43%)	⬇️
label_studio/label_studio/core/utils/contextlog.py	44.55% <0.00%> (-2.33%)	⬇️
label_studio/label_studio/tasks/serializers.py	84.27% <0.00%> (-2.27%)	⬇️
label_studio/label_studio/tasks/models.py	87.85% <0.00%> (-2.20%)	⬇️
...abel_studio/label_studio/data_manager/functions.py	64.70% <0.00%> (-1.97%)	⬇️
... and 53 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 11164d2...36046e1. Read the comment docs.

[aisensiy]

I do not get the reason that gitleaks failed...