Do not delete database when deleting plugin

Hi,

I updated Contact Form 7 from 5.1.1 to 5.1.6 and noted that “subscribers_only: true” was hiding the forms for logged in users (I want to talk about this issue latter). Then, I removed the 5.1.6 to revert back to 5.1.1. I noted that all my forms were deleted together. I think that would be nice to have an option to keep the database in case we remove Contact Form 7.

Thanks for such a great plugin!