CCM-4996: Remove channel enriched from GET message endpoint

[simonlabarere]

Summary

Updated:

• sandbox to remove the "enriched" timestamp from channels in the GET Message examples
• the Open API Specs to remove the "enriched" timestamp from channel

Notes:

• There is still an enriched timestamp present at the attributes level, this is intentional
• While the tests checked for the presence of a timestamps object within a channel item, they did not check individual timestamps within it so they didn't need to be updated

OAS Update:

Reviews Required

• Dev
• Test
• Tech Author
• Product Owner

Checklist

• Brief description of work completed, and any technical decisions made as part of the PR
• PR link added as a comment to the relevant JIRA ticket
• PR link shared on Slack and/or Teams
• 2 reviews received
• Tester approval

[github-actions]

This branch is work on a ticket in the NHS Digital APM JIRA Project. Here's a handy link to the ticket:

CCM-4996

[github-actions]

This branch is work on a ticket in the NHS Digital APM JIRA Project. Here's a handy link to the ticket:

CCM-4996

[github-actions]

This branch is work on a ticket in the NHS Digital APM JIRA Project. Here's a handy link to the ticket:

CCM-4996

[github-actions]

This branch is work on a ticket in the NHS Digital APM JIRA Project. Here's a handy link to the ticket:

CCM-4996