While there is no dedicated app that would copy over email engagement from Mailchimp to HubSpot you could use Outfunnel’s free trial to do a one-off data import. Our HubSpot-Mailchimp integration is designed to sync email engagements over constantly but if you set up a new connection you could choose to do a one-off historic engagement sync. And - if ongoing sync is not relevant for you, you can just delete the connection after email engagements have synced over and let the free trial expire.
Each email activity recorded to a contact profile would not contain the email HTML but it would contain the name of the campaign.
You can sign up for the free trial via the HS marketplace