screen_ui: Fix a case that may truncate the last char.

ScreenRecoveryUI::DrawWrappedTextLines() should be called with
kMarginWidth only. Because it's using a line limit of text_cols_,
which is unaware of kMenuIdent.

Bug: 64293520
Test: No missing char with long header text.
Change-Id: Ib4d08de2c56473a483ff9964eb6cec31f8a74c9a