Bump form-data and firebase-admin in /functions/testapp/functions

---
updated-dependencies:
- dependency-name: form-data
  dependency-version: 2.5.5
  dependency-type: indirect
- dependency-name: firebase-admin
  dependency-version: 13.4.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]