chore: use Contains or ErrorContains with testify

[mmorel-35]

Description of the changes

• use Contains or ErrorContains with testify
• remove useless Error check before ErrorContains check

How was this change tested?

• CI

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.49%. Comparing base (1378e91) to head (eafd0e1).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6161   +/-   ##
=======================================
  Coverage   96.49%   96.49%           
=======================================
  Files         354      354           
  Lines       20126    20126           
=======================================
  Hits        19420    19420           
  Misses        522      522           
  Partials      184      184           

Flag	Coverage Δ
badger_v1	8.31% <ø> (ø)
badger_v2	1.67% <ø> (ø)
cassandra-4.x-v1	14.39% <ø> (ø)
cassandra-4.x-v2	1.61% <ø> (ø)
cassandra-5.x-v1	14.39% <ø> (ø)
cassandra-5.x-v2	1.61% <ø> (ø)
elasticsearch-6.x-v1	18.59% <ø> (-0.01%)	⬇️
elasticsearch-7.x-v1	18.68% <ø> (+<0.01%)	⬆️
elasticsearch-8.x-v1	18.85% <ø> (ø)
elasticsearch-8.x-v2	1.67% <ø> (+0.01%)	⬆️
grpc_v1	9.48% <ø> (ø)
grpc_v2	6.99% <ø> (-0.01%)	⬇️
kafka-v1	8.88% <ø> (ø)
kafka-v2	1.67% <ø> (?)
memory_v2	1.67% <ø> (ø)
opensearch-1.x-v1	18.72% <ø> (ø)
opensearch-2.x-v1	18.72% <ø> (ø)
opensearch-2.x-v2	1.67% <ø> (ø)
tailsampling-processor	0.46% <ø> (ø)
unittests	95.40% <ø> (ø)

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[yurishkuro]

Wow, this is a massive clean up 🤩

many thanks 🙏 🚀