[INT-6993] ATS SAP SF T2 hub Doc merge

[sourabh-stackone]

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Summary by cubic

Merged the Teamtailor assessment/background check setup into one guide and added Marketplace activation steps using the External Trigger Token. Aligns with INT-6993 by combining “Enable Partner app” and “Steps to send test” into a single flow.

• Refactors
  • Added “Activate Marketplace Integration” section with steps to get the External Trigger Token from StackOne Connector Hub and activate in Teamtailor Marketplace.
  • Updated page description to mention the StackOne connection.
  • Consolidated sending the test and checking results into one page with screenshots.

[Copilot]

Pull Request Overview

This PR adds documentation for activating Teamtailor Marketplace Integration with StackOne, providing step-by-step instructions for users to establish the connection using an External Trigger Token.

• Updates the description to clarify the integration with StackOne
• Adds a new section "Activate Marketplace Integration from Teamtailor" with detailed setup steps
• Includes visual guides with screenshots for the marketplace activation process

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