O-RAN devicemanger should use "event-time" and not "eventTime" for notification mapping.

Result of discussion with demx8as6  about this to specify for O-RAN Devicemanager a consistent behaviour for requesting alarm list and alarm notification. 

Example with Commscope/Winlab over adapter:

2024-02-29T08:25:04,182 | TRACE | nioEventLoopGroup-4-11 | NetconfDeviceCommunicator        | 324 - org.opendaylight.netconf.sal-netconf-connector - 5.0.7 |  -  | RemoteDeviceId[name=172.60.0.34, address=/172.60.0.34:55308]: Notification received: <notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
    <eventTime>2024-02-29T08:25:04.171964471+00:00</eventTime>    <---- DON'T USE  THIS
    <alarm-notif xmlns="urn:o-ran:fm:1.0">
        <fault-id>51</fault-id>
        <fault-source>/ietf-hardware:hardware/component[name='1.0.RFD.R1.1']</fault-source>
        <affected-objects>
            <name>1.0.RFD.R1.1</name>
            <identifier xmlns:hw="urn:ietf:params:xml:ns:yang:ietf-hardware">/hw:hardware/hw:component[hw:name='1.0.RFD.R1.1']</identifier>
        </affected-objects>
        <fault-severity>MAJOR</fault-severity>
        <is-cleared>false</is-cleared>
        <fault-text>thresholdCrossed</fault-text>
        <probable-cause/>
        <specific-problem/>
        <proposed-repair-actions/>
        <event-time>2024-02-29T09:33:31.000+00:00</event-time>          <----- USE THIS
        <additional-information>
            <identifier>alarm-id</identifier>
            <information>8011</information>
        </additional-information>
        <additional-information>
            <identifier>adapter-event-time</identifier>
            <information>2024-02-29 08:25:04.169952</information>
        </additional-information>
        <alarm-type>EQUIPMENT-ALARM</alarm-type>
    </alarm-notif>
</notification>