Test whether:
* "Enable previews" footer link correctly appears/disappears;
* A hovercard correctly shows/doesn't show when enabled/disabled.
Bug: T133054
Change-Id: I55f311b6b8845e6ebf4cc5698758afd1f9042a45
* Wait until the form submits successfully, verifying it
worked by testing for the notification toast.
* Drop sleep statements where possible - instead use when_present
Use one when asserting something doesn't show to avoid false positives
* Allow more time for the hovercard to show (5s) - API requests might take
longer than default time.
* Assert popups JavaScript loads before continuing with test. This
helped trap a bug in testing and will be useful for future.
Bug: T133019
Depends-On: Icb1e6ddc8f95da5e4b4de2916d292694c11ba731
Change-Id: Iacd3beedf44cadffcf0285231b2df7e5b64294f6
Basic feature of browsing a page, hovering a link, and showing/hiding
a hovercard.
Depends-On: Ie94fa399512be041f12b2f7cada20d4206ddaf82
Bug: T133019
Change-Id: Idf39e7e2a3b343babd6d0538225b4ef9002e8ac1
