Fix the crash in LT-14519

When the display single gram. info first option is
configured and there are entries with no MSAs it should
not result in a crash. Just don't display the non existant
gram. info.
[Wussing out on unit tests because of time pressure and the
impressive lack of any useful tests for this legacy class]

Change-Id: I7c0a380acc180cfe02714ec4d38fd7bfa9a484ef