Add maxlines bounds to the category title.

- So far, none of the translations exceeded 1-line, but setting maxlines
to avoid it to happen in future.

* http://screen/35PYFHV5SCeBhqC (at max font size)

Bug: N/A
Flag: ACONFIG com.android.launcher3.enable_categorized_widget_suggestions TEAMFOOD
Test: Manual - see videos.
Change-Id: I263706a5d85dd4a37a4150abd58222283d5e039a