fixed custom json encoders

[AndrewChubatiuk]

What type of PR is this?

Fixes #6737

• Refactor
• Feature
• Bug Fix
• New Query Runner (Data Source)
• New Alert Destination
• Other

Description

How is this tested?

• Unit tests (pytest, jest)
• E2E Tests (Cypress)
• Manually
• N/A

Related Tickets & Documents

Mobile & Desktop Screenshots/Recordings (if there are UI changes)

[guidopetri]

@AndrewChubatiuk , thanks for the PR. Could you explain the change + test it somehow before we merge?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (d245ff7) 63.37% compared to head (9e79a25) 63.37%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #6741   +/-   ##
=======================================
  Coverage   63.37%   63.37%           
=======================================
  Files         162      162           
  Lines       13170    13170           
  Branches     1819     1819           
=======================================
  Hits         8347     8347           
  Misses       4532     4532           
  Partials      291      291           

Files	Coverage Δ
redash/query_runner/cass.py	45.05% <100.00%> (ø)
redash/query_runner/mongodb.py	40.29% <100.00%> (ø)
redash/query_runner/pg.py	41.75% <100.00%> (ø)
redash/utils/__init__.py	70.71% <100.00%> (ø)

[AndrewChubatiuk]

@AndrewChubatiuk , thanks for the PR. Could you explain the change + test it somehow before we merge?

this change is actually a typo fix for custom json encoders loading which was introduced after migration of almost all json columns from TEXT to JSONB column type in postgres
tested it locally with a local mongodb instance
proof.pdf

[guidopetri]

Merging because it seems it'll fix an issue, but I'm not sure I understand the change. Please try to be more descriptive when creating PRs so that everyone can follow along!