Bug 1743780 - Get rid of PuppetScreenManager and PuppetScreen. r=emilio

Now we use `mozilla::widget::ScreenManager` even if on content process, so no
one uses `PuppetScreen` and `PuppetScreenManager`.

And I would like to remove `Hal.h` reference from `PuppetWidget`, so I remove
unused method.

Differential Revision: https://phabricator.services.mozilla.com/D132564