BD-3577: Clarify message consent for spam regulations

[lydia-xie]

Why are you making this change? (required)

Clarify message consent for spam regulations

Related PRs, issues, or features (optional)

• BD-3577

Feature release date (optional)

• N/A

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• I confirm that my PR meets the following:
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Thanks for contributing! We look forward to reading your work.

[rachel-feinberg]

Lgtm1