build(deps): bump fast-xml-parser and openapi-sampler in /rest-gateway (#1502)

Bumps [fast-xml-parser](https://github.com/NaturalIntelligence/fast-xml-parser) and [openapi-sampler](https://github.com/redocly/openapi-sampler). These dependencies needed to be updated together.

Updates `fast-xml-parser` from 4.5.3 to 5.4.1
- [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@v4.5.3...v5.4.1)

Updates `openapi-sampler` from 1.6.2 to 1.7.0
- [Release notes](https://github.com/redocly/openapi-sampler/releases)
- [Commits](https://github.com/redocly/openapi-sampler/commits)

---
updated-dependencies:
- dependency-name: fast-xml-parser
  dependency-version: 5.4.1
  dependency-type: indirect
- dependency-name: openapi-sampler
  dependency-version: 1.7.0
  dependency-type: indirect
...

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Author: dependabot[bot]