Convert partial level 2 files to typescript for contributing to `metamask-controller.js`

[DDDDDanica]

Convert dependency of files for metamask-controller.js (level 2) we want to target based on typescript migration dashboard.

Level 2

• app/scripts/controllers/detect-tokens.js
• app/scripts/controllers/ens/index.js
• app/scripts/controllers/metametrics.js
• app/scripts/controllers/swaps.js
• app/scripts/lib/ComposableObservableStore.js
• app/scripts/lib/createMetaRPCHandler.js
• app/scripts/lib/createRPCMethodTrackingMiddleware.js