[FEAT]: Offline notice for fetch failed generic error

[timothycarambat]

What would you like to see?

This issue is specific for desktop users, but can occur to anyone who wants to use AnythingLLM offline and

• has the AnythingLLM built-in embedder model
• has not downloaded the model yet as they have not embedded a document yet.

When they attempt to embed, the fallback URL will still not work - resulting in a fetch failed error when a more apt error would be Internet connection required or something along those lines.