[Fleet] api/fleet/agents returning 500 when component field has format different than expected

[criamico]

Kibana version:
8.16.2 and above

Describe the bug:

User in cloud has a job which exports agent statistics running this query:

api/fleet/agents?perPage=9999&withMetrics=false&showInactive=true&getStatusSummary=true&kuery=%28not+policy_id%3A+policy-elastic-agent-on-cloud+and+not+status+%3A+unenrolled%29

Sometimes this fails with error

`{"statusCode":500,"error":"Internal Server Error","message":"_hit$_source4.components.map is not a function"}`

The error occurs here when the components field contains unexpected data.

Fleet expects this field to always be an array having this format:

"components": [
  {
    "id": "fleet-server-es-containerhost",
    "message": "Healthy: communicating with pid '187'",
    "status": "HEALTHY",
    "type": "fleet-server",
    "units": []
  }
]

However in some cases it was observed to be missing or to be a string and this triggered the error:

"components": "W3siaWQiOiJ3aW5kb3dzLlIjoiU3RhcnRplkICc0NTCI6ImUyJyJ9XX1d"

One thing to investigate is why sometimes this field has a different content than expected, did it change something in Fleet Server or it's due to an error?

Steps to reproduce:
I'm not sure how to reproduce it the actual error, as it was observed in production.
However it can be forced locally by inserting some data with the invalid format in the fleet agents index.

Expected behavior:
Fleet should handle more gracefully this type of "invalid" documents instead of breaking the api response.

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[criamico]

I created this ticket but then I noticed that this bug was recently fixed in Fleet UI by #207746, available from version 8.18.0 and above.