updates privacy consent notice to include note about collected health metrics

[hamilton]

This addresses an issue in (but does not close) #371 – the study consent notice will need to be updated to include these barebones health metrics.

Checklist for reviewer:

• The description should reference a bug or github issue, if relevant.
• There must be a CHANGELOG.md entry for any non-test change.
• Any change to the NPM commands must be carefully reviewed to make sure it won't break the Add-ons pipeline.
• Any version increase must follow the release process.

[Dexterp37]

Let's hold back this until the discussion in #371 is finalized.

[Dexterp37]

@hamilton can we close this? We're no longer doing it :)