Expand search bar text to vertically fit on small devices.

The text "Search contacts & places" gets cut off because the small size
of certain devices causes the text to spill over to a second line. Use
"wrap_content" for height instead of "search_box_icon_size"

Bug: 18552411
Change-Id: I2263aca687d1d2a431146d057099980970df75f0