Prevent Checkstyles on External Code (#17766)
Prevent Checkstyles on External Code (#17766)

* Exclude code from external libraries being included in Checkstyle checking

* Add comment explaining the excludes configuration
Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java