screen_ui: Word-wrap menu headers.

This CL adds ScreenRecoveryUI::DrawWrappedTextLines() to better handle
long menu header texts. It does a word wrap at spaces, if available.
This avoids fixed-length menu headers being truncated on small screens.

Bug: 64293520
Test: On bullhead, boot into recovery with --prompt_and_wipe_data, and
      check the prompt texts.
Change-Id: Ia22746583516dd230567a267584aca558429395e