SystemUI: global actions: fix icon position on multi-line action

Some languages (such as Finnish) have reboot text over 2 lines.
Set the top margin of the message to 0dp when there is more than
1 line of text and to 14dp when there is only 1 line.
Fixes issue where icon is not inline  with other icons on a tile
with multi-line message.

Test: verify icons are aligned on different dpi's in power menu.

Signed-off-by: Timi Rautamäki <timi.rautamaki@gmail.com>
Change-Id: I4320e46a14e671e1176da14f8210604c7c9470d2