Update concepts-messaging.md (#4835)
Update concepts-messaging.md (#4835)

The name in the text description does not match the name in the diagram.


https://pulsar.apache.org/docs/en/next/concepts-messaging/#failover
The figure pulsar-failover-subscriptions.png contains only Consumer-B-0 and Consumer-B-1;


https://pulsar.apache.org/docs/en/next/concepts-messaging/#shared
The figure pulsar-shared-subscriptions.png contains only Consumer-C-1, Consumer-C-2 and Consumer-C-3.
yahoo/pulsar,massakam/pulsar,massakam/pulsar,merlimat/pulsar,merlimat/pulsar,yahoo/pulsar,massakam/pulsar,massakam/pulsar,yahoo/pulsar,massakam/pulsar,massakam/pulsar,yahoo/pulsar,merlimat/pulsar,merlimat/pulsar,yahoo/pulsar,yahoo/pulsar,merlimat/pulsar,merlimat/pulsar