Search suggestions dropdown does not dismiss when clicking out of it

Created by: sqs

Repro:

1. Go to https://sourcegraph.com/github.com/sourcegraph/sourcegraph@39f93e5/-/blob/enterprise/cmd/frontend/auth/saml/middleware.go#L122
2. In the search query input, type any letter (such as a)
3. Wait for the search suggestions dropdown to show up (as expected)
4. Click in the blob view

Expected: clicking in the blob view should dismiss the search suggestions dropdown.

Actual: sometimes it dismisses it but then it comes back again in 1-3s. Sometimes it doesn't dismiss it at all.