fix(redirect): app.use => app.get

app.use applies to all requests that match a given path, including
requests to subpaths. This results in redirects for URLs that are
incorrect, including `/short-url/unwanted/path`.

Correct this by specifying that only GETs to short URL paths should
be handled.

src/server/index.ts

@@ -175,7 +175,7 @@ initDb()
       '/assets/transition-page/js/redirect.js',
       redirectController.gtagForTransitionPage,
     )
-    app.use(
+    app.get(
       '/:shortUrl([a-zA-Z0-9-]+)',
       ...redirectSpecificMiddleware,
       redirectController.redirect,