[EPIC] Source Harvest to Beta

[igrankova]

The main purpose of this issue is to track release progress for the connector.

According to checklist:

• MLP improvements, based on doc:

  None

• All outstanding bug reports blocking Beta:

  • Harvest source connector doesn't sync parent_id for parent/child data (Ex: Invoices/InvoiceMessages) #10350
  • Harvest “started_time” being incorrectly cast as datetime field #11980

• Other improvements:

  • Source Harvest: increase unit test coverage at least 90% #15219
  • 🎉 Source Harvest: Update releaseStage to beta #15614

Acceptance criteria

• Create a checklist document that should be placed on the Google Drive
• Checklist filled up by engineering team
• Collect and list all tech debt-related issues in the section below
• Create/Revise MLP document and place it here
• Move checklist to the unblockers team
• Reviewed/Updated by unblockers team
• Move checklist to the product team for review
• Reviewed/Updated by product team
• Update connector documentation according to the comments in the checklist
• Certification completed

[YowanR]

LGTM -- thank you!