stats: emit stats for retries (#718)
stats: emit stats for retries (#718)

Adding the following stats to the allow-list based on [these Envoy docs](https://www.envoyproxy.io/docs/envoy/latest/configuration/upstream/cluster_manager/cluster_stats):

- `upstream_rq_retry`
- `upstream_rq_retry_overflow`
- `upstream_rq_retry_success`

Also re-alphabetized the stats list.

Signed-off-by: Michael Rebello <b1c1d8736f20db3fb6c1c66bb1455ed43909f0d8@michaelrebello.com>
envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile