Updated brightness dialog width logic

The new default width for brightness slider UI  when in
landscape mode is half width. However for settings we want full width. Hence now settings
will also send a boolean along with the Intent to start brightness
dialog activity, specifying that the width of the brightness dialog
should be full width.

Test: open settings->display. click or press "Brightness Level" and
check that the brightness slider UI takes the full width of the right
hand pane of settings
Fixes: 303633970

Change-Id: I82d0c33e533bd366d68d8dcba9c9e741144481ac