Remove dependents of language_models (#25511)

This PR removes the dependents of the `language_models` crate.

The following types have been moved from `language_models` to
`language_model` to facilitate this:

- `LlmApiToken`
- `RefreshLlmTokenListener`
- `MaxMonthlySpendReachedError`
- `PaymentRequiredError`

With this change only `zed` now depends on `language_models`.

Release Notes:

- N/A

crates/assistant2/src/thread.rs

@@ -10,9 +10,9 @@ use gpui::{App, Context, EventEmitter, SharedString, Task};
 use language_model::{
     LanguageModel, LanguageModelCompletionEvent, LanguageModelRegistry, LanguageModelRequest,
     LanguageModelRequestMessage, LanguageModelToolResult, LanguageModelToolUse,
-    LanguageModelToolUseId, MessageContent, Role, StopReason,
+    LanguageModelToolUseId, MaxMonthlySpendReachedError, MessageContent, PaymentRequiredError,
+    Role, StopReason,
 };
-use language_models::provider::cloud::{MaxMonthlySpendReachedError, PaymentRequiredError};
 use serde::{Deserialize, Serialize};
 use util::{post_inc, TryFutureExt as _};
 use uuid::Uuid;