Counter name in 'identity.authenticate.' metric doesn't render correctly

[Yadnesh Kulkarni]

~~~
Payload={'message_id': 'be5ccc6e-2eb8-4423-8a23-d90d202c44b3', 'publisher_id': 'telemetry.publisher.jt-ecosys-ctrl02-l4-r3-u23.cloud.internal', 'event_type': 'metering', 'priority': 'SAMPLE', 'payload': [{'source': 'openstack', 'counter_name': "$.payload.outcome - $.payload.outcome + 'identity.authenticate.' + $.payload.outcome",'action': 'authenticate', 'outcome': 'failure'}
~~~

'counter_name' in above metric should've been rendered as 'identity.authenticate.failure' or 'identity.authenticate.success' depending upon the 'outcome' field in the payload.

Scrapping tools like Prometheus fail to scrape these metrics due to invalid metric names.
~~~
2023-06-19 08:34:34 [ERROR] prometheus failed scrapping metric [plugin: Prometheus, error: "ceilometer_$_payload_outcome - $_payload_outcome + 'identity_authenticate_' + $_payload_outcome" is not a valid metric name]
2023-06-19 08:34:34 [ERROR] prometheus failed scrapping metric [plugin: Prometheus, error: "ceilometer_$_payload_outcome - $_payload_outcome + 'identity_authenticate_' + $_payload_outcome" is not a valid metric name]
2023-06-19 08:34:34 [ERROR] prometheus failed scrapping metric [plugin: Prometheus, error: "ceilometer_$_payload_outcome - $_payload_outcome + 'identity_authenticate_' + $_payload_outcome" is not a valid metric name]
~~~

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/ceilometer zed-eom release.