Wrong event name for StateUpdatedEvent / StateChangedEvent

[spacemanspiff2007]

The new fields for last change / last update have different names in different events making them very hard to consume.

• ItemStateUpdatedEvent -> lastUpdate
• ItemStateChangedEvent -> lastStateUpdate + lastStateChange

{"type": "ItemStateUpdatedEvent", "topic": "openhab/items/SwPKEghgdy/stateupdated", "payload": {"type": "OnOff", "value": "OFF", "lastUpdate": "2025-04-23T22:18:25.0464742+02:00[Europe/Berlin]"}}
{"type": "ItemStateChangedEvent", "topic": "openhab/items/SwPKEghgdy/statechanged", "payload": {"type": "OnOff", "value": "OFF", "oldType": "OnOff", "oldValue": "ON", "lastStateUpdate": "2025-04-23T22:18:25.0464742+02:00[Europe/Berlin]", "lastStateChange": "2025-04-23T22:18:25.0464742+02:00[Europe/Berlin]"}}

{"type": "GroupStateUpdatedEvent", "topic": "openhab/items/GrpKBDxvsz/SwRTRevpbt/stateupdated", "payload": {"type": "OnOff", "value": "OFF", "lastUpdate": "2025-04-23T22:18:31.0302278+02:00[Europe/Berlin]"}}
{"type": "GroupItemStateChangedEvent", "topic": "openhab/items/GrpKBDxvsz/SwRTRevpbt/statechanged", "payload": {"type": "OnOff", "value": "OFF", "oldType": "OnOff", "oldValue": "ON", "lastStateUpdate": "2025-04-23T22:18:31.0302278+02:00[Europe/Berlin]", "lastStateChange": "2025-04-23T22:18:31.0302278+02:00[Europe/Berlin]"}}

Please align the field names

#4601 #4351

[jimtng]

Good catch!