Report telemetry events for rate limit errors (#16130)

clickhouse telemetry schema:

```
CREATE TABLE default.llm_rate_limit_events
(
    `time` DateTime64(3),
    `user_id` Int32,
    `is_staff` Bool,
    `plan` LowCardinality(String),
    `model` String,
    `provider` LowCardinality(String),
    `usage_measure` LowCardinality(String),
    `requests_this_minute` UInt64,
    `tokens_this_minute` UInt64,
    `tokens_this_day` UInt64,
    `max_requests_per_minute` UInt64,
    `max_tokens_per_minute` UInt64,
    `max_tokens_per_day` UInt64,
    `users_in_recent_minutes` UInt64,
    `users_in_recent_days` UInt64
)
ORDER BY tuple()
```

Release Notes:

- N/A

Co-authored-by: Marshall <marshall@zed.dev>

crates/collab/src/llm/telemetry.rs

@@ -19,9 +19,38 @@ pub struct LlmUsageEventRow {
     pub spending_this_month: u64,
 }
 
+#[derive(Serialize, Debug, clickhouse::Row)]
+pub struct LlmRateLimitEventRow {
+    pub time: i64,
+    pub user_id: i32,
+    pub is_staff: bool,
+    pub plan: String,
+    pub model: String,
+    pub provider: String,
+    pub usage_measure: String,
+    pub requests_this_minute: u64,
+    pub tokens_this_minute: u64,
+    pub tokens_this_day: u64,
+    pub users_in_recent_minutes: u64,
+    pub users_in_recent_days: u64,
+    pub max_requests_per_minute: u64,
+    pub max_tokens_per_minute: u64,
+    pub max_tokens_per_day: u64,
+}
+
 pub async fn report_llm_usage(client: &clickhouse::Client, row: LlmUsageEventRow) -> Result<()> {
     let mut insert = client.insert("llm_usage_events")?;
     insert.write(&row).await?;
     insert.end().await?;
     Ok(())
 }
+
+pub async fn report_llm_rate_limit(
+    client: &clickhouse::Client,
+    row: LlmRateLimitEventRow,
+) -> Result<()> {
+    let mut insert = client.insert("llm_rate_limits")?;
+    insert.write(&row).await?;
+    insert.end().await?;
+    Ok(())
+}