Fix #1969

[tobiasBora]

This fixes #1969 (a type was not exported)

Note to myself and other people that want to test/contribute to dexie.js

1. Clone dexie.js, install pnpm (I used nix-shell -p nodePackages.pnpm, npm will not work here), and run pnpm install in the root folder of Dexie, pnpm build in the root folder to build dexie.js (not sure if needed for addons), and go to addons/dexie-export-import/, and also run these two commands. This should create a dist folder.
2. From the addons/dexie-export-import/, run npm link
3. From your project, run npm link dexie-export-import, it should make node_modules/dexie-export-import point (via a symlink) to your copy of dexie project. Everytime you change dexie, make sure to rebuild it.