[BUG][9.0/Serverless] Screenshot needs to be replaced as per current Kibana UI because integrations label is removed (#1347)

Contributes to #1217 by
fixing outdated screenshots of the Rules page and integrations design in
the 9.0/Serverless docs.

Preview: [Manage detection
rules](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/1347/solutions/security/detect-and-alert/manage-detection-rules)

Corresponding 8.18 PR:
elastic/security-docs#6818

Author: nastasha-solomon