clean: Avoid depending on two json libraries

[lolgab]

Remove ujson dependency

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ +0.26% (target: -1.00%)	✅ ∅

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (9cc735f)	380	343	90.26%
Head commit (aadbb50)	380 (+0)	344 (+1)	90.53% (+0.26%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#495)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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_{You may notice some variations in coverage metrics with the latest Coverage engine update. For more details, visit the documentation}

[DMarinhoCodacy]

LGTM!