JetBrains: Move title into web view and add loading indicator

Created by: philipp-spiess

This PR moves the modal title into the web view so that we can add the loading indicator similar to what we explored in the Figma draft:

We worked around the issue of the popover no longer being moveable by rendering the title and icon only in the native popover title component and moving the loading indicator into the status bar.

Test plan

https://user-images.githubusercontent.com/458591/170710940-a563092b-f0f2-4a17-85a7-3ef4ae97a46c.mov

App preview:

• Web
• Storybook

Check out the client app preview documentation to learn more.