pulsar_client_consumer_processing_time_seconds metric records incorrect values

#### Expected behavior

The `pulsar_client_consumer_processing_time_seconds` metric should contain observations of the time it takes a consumer to process messages.

#### Actual behavior

The observations are wrong. They have values of approximately 8.5e+09 (~269 years).

#### Steps to reproduce
Create a consumer, ack some messages, check the metrics. e.g.
```
func main() {
http.Handle("/metrics", promhttp.Handler())
go http.ListenAndServe(":9090", nil)

client, err := pulsar.NewClient(pulsar.ClientOptions{
URL: URL,
Authentication: pulsar.NewAuthenticationToken(TOKEN),
})
if err != nil {
panic(err)
}
defer client.Close()

consumer, err := client.Subscribe(pulsar.ConsumerOptions{
Topic: TOPIC,
Name: "test-consumer",
SubscriptionName: "test-subscription",
})
if err != nil {
panic(err)
}

msg, err := consumer.Receive(context.Background())
if err != nil {
panic(err)
}

err = consumer.Ack(msg)
if err != nil {
panic(err)
}

time.Sleep(time.Hour)
}
```
produces
```
# HELP pulsar_client_consumer_processing_time_seconds Time it takes for application to process messages
# TYPE pulsar_client_consumer_processing_time_seconds histogram
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.0005"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.001"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.005"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.01"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.025"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.05"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.1"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.25"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="0.5"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="1"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="2.5"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="5"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="10"} 0
pulsar_client_consumer_processing_time_seconds_bucket{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN",le="+Inf"} 1
pulsar_client_consumer_processing_time_seconds_sum{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN"} 8.500242974069234e+09
pulsar_client_consumer_processing_time_seconds_count{client="go",pulsar_namespace="HIDDEN",pulsar_tenant="HIDDEN"}
```

#### System configuration
**Pulsar version**: 2.10
**Pulsar client version**:v0.11.1

Start by reproducing the issue with the provided consumer Receive/Ack example and exposing metrics through promhttp.Handler. Search the client for pulsar_client_consumer_processing_time_seconds and the acknowledgement path, then verify that the histogram observes processing time in seconds rather than a large timestamp-like value. Done means the reported value matches the time taken to process messages.

Written by the indexing model from the issue text.