QueueMetrics leaks Configuration objects when validation API is called multiple times

QueueMetrics#QUEUE_METRICS is a static map, which is a source of multiple bugs eg. YARN-11152.

The current scenario could be reproduced by adding queues one at a time via the mutation API.

1. Validate adding queue1 via validation API
2. Validation API instantiates a new CS, with a new Configuration, that instantiates a ConfigurationProperties
3. QueueMetrics does share the same QUEUE_METRICS cache with the original CS, where there is now a Metrics object that belongs to the new CS