Bug 1035250 fte connectivity

So what's best is:
Implement Ftu.isUpgrading as I said in https://bugzilla.mozilla.org/show_bug.cgi?id=1054827#c13
and check
```js
if (!FtuLauncher.isFtuRunning() || (FtuLauncher.isFtuRunning() && !FtuLauncher.isUpgrading())) {
  // full observe
} else {
  // lazy observe
}
```