Redis stats: extract Redis command as Prometheus label in metrics

*Title*: *Extract Redis Command as Prometheus Label in Metrics*

*Description*:
Currently, Redis Prometheus metrics are using the metric name to identify which Redis command is being measured. This makes it difficult to filter and aggregate metrics by command, which is a common use case for monitoring Redis performance.

Redis metrics could be improved by extracting the Redis command name as a Prometheus label (tag), as recommended by Prometheus best practices. This would allow users to easily filter and aggregate metrics by command.

For example, instead of the metric name `envoy_redis_command_mset_total` for the `mset` command, the metric could be labeled as `envoy_redis_command_total{command="mset"}`.

Thank you for considering this feature request.