Bump @wdio/local-runner from 8.11.2 to 8.15.6

Bumps [@wdio/local-runner](https://github.com/webdriverio/webdriverio/tree/HEAD/packages/wdio-local-runner) from 8.11.2 to 8.15.6.
- [Release notes](https://github.com/webdriverio/webdriverio/releases)
- [Changelog](https://github.com/webdriverio/webdriverio/blob/main/CHANGELOG.md)
- [Commits](https://github.com/webdriverio/webdriverio/commits/v8.15.6/packages/wdio-local-runner)

---
updated-dependencies:
- dependency-name: "@wdio/local-runner"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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