build(deps): bump ejs from 3.1.7 to 3.1.9 in /src

Bumps [ejs](https://github.com/mde/ejs) from 3.1.7 to 3.1.9.
- [Release notes](https://github.com/mde/ejs/releases)
- [Commits](https://github.com/mde/ejs/compare/v3.1.7...v3.1.9)

---
updated-dependencies:
- dependency-name: ejs
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

src/package.json

@@ -34,7 +34,7 @@
     "clean-css": "^5.3.2",
     "cookie-parser": "^1.4.6",
     "cross-spawn": "^7.0.3",
-    "ejs": "^3.1.7",
+    "ejs": "^3.1.9",
     "etherpad-require-kernel": "^1.0.15",
     "etherpad-yajsml": "0.0.12",
     "express": "4.18.2",