Bump koa from 2.15.3 to 2.16.1 in /src/Umbraco.Web.UI.Client

Bumps [koa](https://github.com/koajs/koa) from 2.15.3 to 2.16.1.
- [Release notes](https://github.com/koajs/koa/releases)
- [Changelog](https://github.com/koajs/koa/blob/master/History.md)
- [Commits](https://github.com/koajs/koa/compare/2.15.3...v2.16.1)

---
updated-dependencies:
- dependency-name: koa
  dependency-version: 2.16.1
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

src/Umbraco.Web.UI.Client/package-lock.json

@@ -10881,9 +10881,9 @@
 			}
 		},
 		"node_modules/koa": {
-			"version": "2.15.3",
-			"resolved": "https://registry.npmjs.org/koa/-/koa-2.15.3.tgz",
-			"integrity": "sha512-j/8tY9j5t+GVMLeioLaxweJiKUayFhlGqNTzf2ZGwL0ZCQijd2RLHK0SLW5Tsko8YyyqCZC2cojIb0/s62qTAg==",
+			"version": "2.16.1",
+			"resolved": "https://registry.npmjs.org/koa/-/koa-2.16.1.tgz",
+			"integrity": "sha512-umfX9d3iuSxTQP4pnzLOz0HKnPg0FaUUIKcye2lOiz3KPu1Y3M3xlz76dISdFPQs37P9eJz1wUpcTS6KDPn9fA==",
 			"dev": true,
 			"license": "MIT",
 			"dependencies": {