chore(deps): bump @react-navigation/stack from 7.6.4 to 7.6.8

Bumps [@react-navigation/stack](https://github.com/react-navigation/react-navigation/tree/HEAD/packages/stack) from 7.6.4 to 7.6.8.
- [Release notes](https://github.com/react-navigation/react-navigation/releases)
- [Changelog](https://github.com/react-navigation/react-navigation/blob/@react-navigation/stack@7.6.8/packages/stack/CHANGELOG.md)
- [Commits](https://github.com/react-navigation/react-navigation/commits/@react-navigation/stack@7.6.8/packages/stack)

---
updated-dependencies:
- dependency-name: "@react-navigation/stack"
  dependency-version: 7.6.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

package-lock.json

@@ -29,7 +29,7 @@
     "@react-native-picker/picker": "^2.8.1",
     "@react-native/new-app-screen": "0.81.0",
     "@react-navigation/native": "^7.1.21",
-    "@react-navigation/stack": "^7.6.4",
+    "@react-navigation/stack": "^7.6.8",
     "prop-types": "^15.8.1",
     "react": "19.1.0",
     "react-native": "0.81.0",