Make fwdata api respect nullable return types#2048

myieye merged 2 commits intodevelopsillsdev/languageforge-lexbox:developfrom

2047-fwdata-throws-instead-of-returning-null-when-entity-not-foundsillsdev/languageforge-lexbox:2047-fwdata-throws-instead-of-returning-null-when-entity-not-foundCopy head branch name to clipboard