This makes the weather suggestion blockable. It depends on the new `isBlockable`
payload property added in D163766. The suggestion's row in the view will
automatically get a block button by setting that property.
We don't have an existing browser-chrome test for the block button by itself to
make sure picking it removes the row, so I added a task to
browser_remove_match.js.
The change to test_weather.js makes sure calling `blockResult()` on the provider
correctly disables the `suggest.weather` pref.
Depends on D163766
Differential Revision: https://phabricator.services.mozilla.com/D164120
05d8fae55e