Internal error `Error while generating embeddings` on wrong url

[mdubus]

Describe the bug

Trying to add an embedder with a wrong URL, I got an internal error on v1.8 rc-1 and rc-2 (but not rc-0)

To Reproduce Steps to reproduce the behavior:

Try to add the following embedder:

   "default": {
        "source": "ollama",
        "url": "http://localhost:11434/api/embeddings",
        "apiKey": "<your-ollama-api-key>",
        "model": "nomic-embed-text",
        "distribution": {
            "mean": 0.7,
            "sigma": 0.3
        }
    }

Then wait a bit for the task to fail. The task should say:

 "error": {
                "message": "internal: Error while generating embeddings: runtime error: could not determine model dimensions: test embedding failed with runtime error: could not reach embedding server: http://localhost:11434/api/embeddings: Connection Failed: Connect error: Address not available (os error 99).",
                "code": "internal",
                "type": "internal",
                "link": "https://docs.meilisearch.com/errors#internal"
            },

Expected behavior Not sure if this is an improvement or a regression, so not sure about the behaviour :)

Meilisearch version: v1.8.0-rc.1 & v1.8.0-rc.2

[dureuill]

Hello,

it is expected that there is an error here. The input URL is wrong, so the operation cannot be expected to complete.

---

It is unexpected that the error is an internal error. It is unclear what kind of error it should be, probably a UserError?

The issue here could come from either:

1. The user typing the wrong URL. OK for a UserError
2. The network is down. Unclear what the error kind should be in the current error scheme.

[dureuill]

As InternalError is going to get us bug reports, a quick fix could be to switch most embedder errors to UserErrors.

The defaults would need to be switched in this From impl

For a longer term fix, see #4620