On Android, most apps include toggles in settings to disable different notification types. It's annoying that they're on by default, but at last you can usually disable them. In Firefox, you can turn off the "Product and feature tips" notifications in settings, and I bet that would prevent that kind of notification appearing. As a last resort, you can disable notifications entirely per-app at the OS level by digging into the Android settings.
It would be nice if Firefox added a separate category for "Political Call to Action" notifications. That way we wouldn't have to miss out on "Product and Feature Tips", which are occasionally helpful. A bit of a moot point for me since I'm using FF on a Nexus 7 that doesn't support that level of selective muting
This notification came through the 'Browser' channel, not 'Mozilla tricks and tips' like you might expect. So, congratulations Mozilla, I've blocked all of the 'Browser' notifications for your browser.