build(deps-dev): bump flatted (#7831)

Bumps [flatted](https://github.com/WebReflection/flatted) from 3.3.3 to 3.4.2.
- [Commits](WebReflection/flatted@v3.3.3...v3.4.2)

---
updated-dependencies:
- dependency-name: flatted
  dependency-version: 3.4.2
  dependency-type: indirect
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

core/generator/gapic-generator-typescript/package-lock.json

@@ -1853,9 +1853,9 @@ flat@^5.0.2:
   integrity sha512-b6suED+5/3rTpUBdG1gupIl8MPFCAMA0QXwmljLhvCUKcUvdE4gWky9zpuGCcXHOsz4J9wPGNWq6OKpmIzz3hQ==
 
 flatted@^3.2.9:
-  version "3.3.3"
-  resolved "https://registry.npmjs.org/flatted/-/flatted-3.3.3.tgz"
-  integrity sha512-GX+ysw4PBCz0PzosHDepZGANEuFCMLrnRTiEy9McGjmkCQYwRq4A/X786G/fjM/+OjsWSU1ZrY5qyARZmO/uwg==
+  version "3.4.2"
+  resolved "https://registry.yarnpkg.com/flatted/-/flatted-3.4.2.tgz#f5c23c107f0f37de8dbdf24f13722b3b98d52726"
+  integrity sha512-PjDse7RzhcPkIJwy5t7KPWQSZ9cAbzQXcafsetQoD7sOJRQlGikNbx7yZp2OotDnJyrDcbyRq3Ttb18iYOqkxA==
 
 foreground-child@^3.1.0:
   version "3.3.1"