Discovered when testing T165579.
Attempting to add a statement with data type "form" on a property fails with "Could not save due to an error. [3f83348963955a7463632683] Exception caught: The given ID does not refer to an entity of type lexeme"
The SetClaim request calls `ReferencedEntitiesDataUpdater::addLinksToParserOutput` when saving the property which in turn attempts to do an `EntityTitleLookup` and calls `EntityHandler::getTitleForId` on the `LexemeHandler` with a `FormId` at which point it breaks because it expected a `LexemeId`.
>>! In T192766#4156688, @Lydia_Pintscher wrote:
> Léa and I just saw the same thing happening when adding a statement on the Lexeme-level of a Lexeme. It was fine on a Form.