[AI-3796] - Remove the `log->source` field from the manifest file

[dkirov-dd]

What does this PR do?

Remove the log->source field from the manifest file

Motivation

This field is no longer needed as it is redundant with the id field in assets/logs/<INTEGRATION_NAME>.yaml

Additional Notes

Review checklist (to be filled by reviewers)

• [ ] Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• [ ] Changelog entries must be created for modifications to shipped code
• [ ] Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• [ ] If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged