Convert policies_list_spec to use testid

What does this MR do and why?

An example of converting a test using data-qa-selector to data-testid

Screenshots or screen recordings

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Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Run from QA directory:

CHROME_HEADLESS=false bundle exec bin/qa Test::Instance::All http://gdk.test:3000/ ./qa/specs/features/ee/browser_ui/10_govern/policies_list_spec.rb

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.