Not showing connection view if the user cannot connect.

[zinigor]

Fixes #8066.

This PR adds a check to the connection view condition. Before we would not show anything to the user if they could not manage modules. Now we add the connect privilege check here as well, so the same thing happens if a user does not have the 'jetpack_connect' cap.

Changes proposed in this Pull Request:

• Adds the connect capability to initial state reducer.
• Adds a check for this capability when determining whether to show the connection view or not.

Testing instructions:

• Disconnect Jetpack.
• Remove connect capability for every user in the client by adding something like false && here: https://github.com/Automattic/jetpack/blob/master/_inc/lib/admin-pages/class.jetpack-react-page.php#L397
• View the dashboard, check that no connection prompts appear.

Proposed changelog entry for your changes:

• Fixed the dashboard view for non-admin users on disconnected sites.

[dereksmart]

Works well, however the page is completely empty when the permissions are not there.

We show this notice to non-admins of the site when it's not connected, and I think the same message still applies:

https://cloudup.com/cbolOw9sIna

Just need to update the logic here
https://github.com/Automattic/jetpack/blob/master/_inc/client/components/jetpack-notices/index.jsx#L206

[zinigor]

Thanks for the review! I have removed the module management cap check and added the connection cap check instead.