[ML] Migrate Mocha unit tests to Jest

[peteharverson]

Meta issue outlining the legacy Mocha unit tests that need to be migrated to Jest.

• ml/common/util
  • anomaly_utils.js ([ML] Converts utils Mocha tests to Jest #63132)
  • job_utils.js (MA) ([ML] Migrate Mocha unit tests to Jest: migrate job utils and query utils tests #63775)
• ml/public/application/components/rule_editor ([ML] Converts utils Mocha tests to Jest #63132)
  • utils.js ([ML] Converts utils Mocha tests to Jest #63132)
• ml/public/application/util/
  • calc_auto_interval.js ([ML] Converts utils Mocha tests to Jest #63132)
  • chart_utils.js ([ML] Converts utils Mocha tests to Jest #63132)
  • string_utils.js ([ML] Converts utils Mocha tests to Jest #63132)
• ml/server/lib
  • query_utils.js (MA) ([ML] Migrate Mocha unit tests to Jest: migrate job utils and query utils tests #63775)
• ml/server/models/bucket_span_estimator (WR)
  • bucket_span_estimator.js (WR)([ML] Migrate server side Mocha tests to Jest. #65651)
• ml/server/models/job_validation (WR)
  • job_validation.js (WR) ([ML] Migrate server side Mocha tests to Jest. #65651)
  • validate_bucket_span.js (WR) ([ML] Migrate server side Mocha tests to Jest. #65651)
  • validate_cardinality.js (WR) ([ML] Migrate server side Mocha tests to Jest. #65651)
  • validate_influencers.js (WR) ([ML] Migrate server side Mocha tests to Jest. #65651)
  • validate_time_range.js (WR) ([ML] Migrate server side Mocha tests to Jest. #65651)

[elasticmachine]

Pinging @elastic/ml-ui (:ml)