Move report_assistant_event into language_model crate (#25508)

This PR moves the `report_assistant_event` function from the
`language_models` crate to the `language_model` crate.

This allows us to drop some dependencies on `language_models`.

Release Notes:

- N/A

Cargo.lock

@@ -395,7 +395,6 @@ dependencies = [
  "language",
  "language_model",
  "language_model_selector",
- "language_models",
  "languages",
  "log",
  "lsp",
@@ -7014,6 +7013,7 @@ dependencies = [
  "anthropic",
  "anyhow",
  "base64 0.22.1",
+ "client",
  "collections",
  "futures 0.3.31",
  "google_ai",
@@ -7029,6 +7029,7 @@ dependencies = [
  "serde_json",
  "smol",
  "strum",
+ "telemetry_events",
  "thiserror 1.0.69",
  "ui",
  "util",
@@ -7081,7 +7082,6 @@ dependencies = [
  "settings",
  "smol",
  "strum",
- "telemetry_events",
  "theme",
  "thiserror 1.0.69",
  "tiktoken-rs",