companion: Remove duplicate typescript dependency

Should only be a devDependency.

packages/@uppy/companion/package.json

@@ -77,7 +77,6 @@
     "request": "2.85.0",
     "serialize-error": "^2.1.0",
     "tus-js-client": "^1.5.1",
-    "typescript": "^2.9.2",
     "uuid": "2.0.2",
     "validator": "^9.0.0",
     "ws": "1.1.5"