Removing PII fields from conversations collection

[galvana]

Purpose

To prevent PII from being returned from the conversations collection. This is meant as a workaround until ethyca/fides#1361 is implemented.

Changes

• Removed PII fields from the conversations collection in the mailchimp_dataset
• Bumped Mailchimp version number

Checklist

• Update CHANGELOG.md file
  • Merge in main so the most recent CHANGELOG.md file is being appended to
  • Add description within the Unreleased section in an appropriate category. Add a new category from the list at the top of the file if the needed one isn't already there.
• Good unit test/integration test coverage
• The Run Unsafe PR Checks label has been applied, and checks have passed, if this PR touches any external services