build(deps): bump submodules/rest-api-specs from ba0c086 to 18f9e9b

Bumps [submodules/rest-api-specs](https://github.com/Azure/azure-rest-api-specs) from `ba0c086` to `18f9e9b`.
- [Release notes](https://github.com/Azure/azure-rest-api-specs/releases)
- [Commits](Azure/azure-rest-api-specs@ba0c086...18f9e9b)

---
updated-dependencies:
- dependency-name: submodules/rest-api-specs
  dependency-version: 18f9e9bfeeccb0f9a44c9902e8478fbe97d2c3c6
  dependency-type: direct:production
...

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

Author: dependabot[bot]