[etcd/tracing]: fix etcd sampling rate flag (#11175)

Signed-off-by: Ugur Ozturk <ugurozturk918@gmail.com>

roles/etcd/templates/etcd.env.j2

@@ -71,7 +71,7 @@ ETCD_EXPERIMENTAL_INITIAL_CORRUPT_CHECK={{ etcd_experimental_initial_corrupt_che
 
 {% if etcd_experimental_enable_distributed_tracing %}
 ETCD_EXPERIMENTAL_ENABLE_DISTRIBUTED_TRACING=true
-ETCD_EXPERIMENTAL_DISTRIBUTED_TRACING_SAMPLE_RATE={{ etcd_experimental_distributed_tracing_sample_rate }}
+ETCD_EXPERIMENTAL_DISTRIBUTED_TRACING_SAMPLING_RATE={{ etcd_experimental_distributed_tracing_sample_rate }}
 ETCD_EXPERIMENTAL_DISTRIBUTED_TRACING_ADDRESS={{ etcd_experimental_distributed_tracing_address }}
 ETCD_EXPERIMENTAL_DISTRIBUTED_TRACING_SERVICE_NAME={{ etcd_experimental_distributed_tracing_service_name }}
 ETCD_EXPERIMENTAL_DISTRIBUTED_TRACING_INSTANCE_ID={{ etcd_member_name }}