Fix reset button being disabled.

- When doing factory reset, we will launch the account credential
confirmation. If this fails, the settings page is re-initialized.
This steps might trigger multiple layout changes for the scrollview
before it is finalized. However, we are removing the global layout
listener once we receive the first update, which could result in the
reset button being disabled incorrectly, as the scroll state is
calculated based on wrong view heights. Remove the call that remove
the layout listener, so that we can still receive further updates.

- also remove the scroll listener once we enable the reset button
from scroll, as no more action is really needed on suceeding scroll.

Change-Id: I6ec1f592991629c15e5ad2bcb29fdd679d598f70
Fixes: 73298075
Test: make RunSettingsRoboTests