fix: update atlas integration tests -- MCP-98

[blva]

Proposed changes

• this fixes the issue where we were validating the size of the response. now we just check if the expected org has been found

Checklist

• I have signed the MongoDB CLA

[Copilot]

Pull Request Overview

This PR fixes an Atlas integration test by removing a hard-coded length validation that was causing test failures. The test now focuses on validating the presence of expected organizations rather than enforcing a specific response size.

• Removes hard-coded length assertion that was brittle and causing test failures
• Maintains validation of the actual organization data content

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[kmruiz]

Added a suggestion, but it's not really blocking.