E2e tests: default to visible:true
Created by: chrismwendt
I expect this to cut down on errors like https://buildkite.com/sourcegraph/sourcegraph/builds/29894#f7b46967-f982-4a35-a995-aa9938440cf9/42-204
Node is either not visible or not an HTMLElement
The default of not waiting for presence regardless of visibility doesn't match my (or the author of this test's) intuition about the behavior of waitForSelector
.