[DOCS] Updates ML/anomaly detection terms in the Kibana guide from 7.1 to 6.5

[szabosteve]

Summary

This PR updates the terminology in the Kibana guide such that it uses appropriate "anomaly detection job" terminology instead of "machine learning job" from 7.1 to 6.5.

Related PR: #41965

Checklist

• [ ] This was checked for cross-browser compatibility, including a check against IE11
• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• [ ] Unit or functional tests were updated or added to match the most common scenarios
• [ ] This was checked for keyboard-only and screenreader accessibility

For maintainers

• [ ] This was checked for breaking API changes and was labeled appropriately
• [ ] This includes a feature addition or change that requires a release note and was labeled appropriately

[elasticmachine]

Pinging @elastic/ml-ui

[szabosteve]

Jenkins, test this

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request