SpecialStatsAddExtra: Format column label with msg

This allows the user of the SpecialStatsAddExtra hook to provide
formatting for the row label using an i18n message key.  If given, the
message is given the row key as a parameter.  To maintain backward
compatibility, the key is used as-is as was done previously if a message
key is not provided.

Bug: T97623
Change-Id: I43c522b24372e115ed78adf69848bf50cbab8295