Stats: hide notices from third-parties on Jetpack > Site Stats page

#### Steps to reproduce the issue

1. While I'm on a wp site that is hosted by Bluehost, I click on `Site Stats` subsection under the `Jetpack` on the left main toolbar:

#### What I expected

I won't expect any message on that page from plugins other than Jetpack.

#### What happened instead

I see third party plugin messages on top of the page.

Reproduce the issue on a WordPress site hosted by Bluehost by opening Jetpack > Site Stats and inspect how notices appear at the top of that page. Identify why third-party plugin messages are shown there; done means the Site Stats page displays Jetpack content without notices from other plugins.

Written by the indexing model from the issue text.