Bump fast-xml-parser from 4.2.4 to 4.3.1 in /testapp

Bumps [fast-xml-parser](https://github.com/NaturalIntelligence/fast-xml-parser) from 4.2.4 to 4.3.1.
- [Release notes](https://github.com/NaturalIntelligence/fast-xml-parser/releases)
- [Changelog](https://github.com/NaturalIntelligence/fast-xml-parser/blob/master/CHANGELOG.md)
- [Commits](NaturalIntelligence/fast-xml-parser@v4.2.4...v4.3.1)

---
updated-dependencies:
- dependency-name: fast-xml-parser
  dependency-type: indirect
...

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