Fixes various small issues

[josenavas]

The User job listing now ignores the hidden jobs
Interaction -> Navigation
The job page now shows the error message if there is one.

[codecov-io]

Codecov Report

Merging #2432 into dev will decrease coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##              dev    #2432      +/-   ##
==========================================
- Coverage   94.09%   94.06%   -0.04%     
==========================================
  Files         163      163              
  Lines       19345    19347       +2     
==========================================
- Hits        18203    18199       -4     
- Misses       1142     1148       +6

Impacted Files	Coverage Δ
qiita_pet/handlers/api_proxy/tests/test_user.py	78.26% <ø> (ø)	⬆️
qiita_db/processing_job.py	93.04% <ø> (ø)	⬆️
qiita_db/user.py	94.83% <100%> (+0.03%)	⬆️
qiita_db/test/test_user.py	99.64% <100%> (ø)	⬆️
qiita_pet/handlers/api_proxy/user.py	53.84% <0%> (-46.16%)	⬇️

---

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 cd2746b...678f8a4. Read the comment docs.

[josenavas]

@ElDeveloper @antgonza are you available to merge?