chore: fix perf advisor test

[blva]

Proposed changes

fixes perf advisor test that was checking for false isError but it's actually undefined

Checklist

• I have signed the MongoDB CLA

[coveralls]

Pull Request Test Coverage Report for Build 19266996495

Warning: This coverage report may be inaccurate.

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Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 80.125%

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Totals
Change from base Build 19234647238:	0.0%
Covered Lines:	6477
Relevant Lines:	7976

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💛 - Coveralls

[Copilot]

Pull Request Overview

This PR fixes a test assertion in the performance advisor integration test that was incorrectly checking for a false value when the actual expected value is undefined.

• Corrects the expected value for response.isError from false to undefined