Update performance indicators for gainsight metrics (2/3)

What does this MR do and why?

This MR adds the customer_health_score value to performance_indicator_type for each health score metric's yml file.

Screenshots or screen recordings

Related Issues/MRs

• Relates to https://gitlab.com/gitlab-data/analytics/-/issues/15392
• !128649 (merged)
• !136233 (closed)

How to set up and validate locally

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

MR acceptance checklist

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