POST Bulk events on Key Event API

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When creating a key event, I would like to be able to post more events per site/ multi events, instead of making each time a POST request per event

**Describe the solution you'd like**
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The API should accept a multi-object array

`POST sites/{siteId}/key-events`
Body:
```
[{
"name": "Broken Internal Links",
"type": "seo",
"time": "2024-02-23T12:28:00.000Z"
}
,{
"name": "FIX:Broken Links",
"type": "seo",
"time": "2024-03-23T19:28:00.000Z"
}]
```

Currently, this fails with 500 ( "message": "Required field \"name\" is missing")

Start by locating the POST sites/{siteId}/key-events entry point and its request validation, then inspect any related API tests. Confirm how a single key event is currently accepted and how validation handles the proposed array. Done means the endpoint accepts multiple event objects for one site, preserves the shown fields, and no longer returns the missing-name 500 for a valid array.

Written by the indexing model from the issue text.