Calendly Block: Can't switch back from link style

As the link style is implemented as a button, once selected the Calendly block changes to the button settings in the inspector and you can't get back to the inline embed

#### Steps to reproduce the issue

1. Insert a Calendly block
2. Select the link style in the inspector

#### What I expected

To be able to switch back to the inline style

#### What happened instead

The block is stuck with button options


I also wasn't seeing the block style previews properly, but I imagine that's a separate issue.

Start at the Calendly block and its inspector by reproducing the two steps described in the issue. Trace the link-style selection and verify that the inspector still allows switching back to the inline embed; done means both styles remain selectable.

Written by the indexing model from the issue text.