collab: Remove unused RateLimiter (#29343)

This PR removes the `RateLimiter` from the collab codebase, as it is no
longer used.

Release Notes:

- N/A

crates/collab/src/lib.rs

@@ -6,7 +6,6 @@ pub mod env;
 pub mod executor;
 pub mod llm;
 pub mod migrations;
-mod rate_limiter;
 pub mod rpc;
 pub mod seed;
 pub mod stripe_billing;
@@ -25,7 +24,6 @@ pub use cents::*;
 use db::{ChannelId, Database};
 use executor::Executor;
 use llm::db::LlmDatabase;
-pub use rate_limiter::*;
 use serde::Deserialize;
 use std::{path::PathBuf, sync::Arc};
 use util::ResultExt;
@@ -295,7 +293,6 @@ pub struct AppState {
     pub blob_store_client: Option<aws_sdk_s3::Client>,
     pub stripe_client: Option<Arc<stripe::Client>>,
     pub stripe_billing: Option<Arc<StripeBilling>>,
-    pub rate_limiter: Arc<RateLimiter>,
     pub executor: Executor,
     pub kinesis_client: Option<::aws_sdk_kinesis::Client>,
     pub config: Config,
@@ -348,7 +345,6 @@ impl AppState {
                 .clone()
                 .map(|stripe_client| Arc::new(StripeBilling::new(stripe_client))),
             stripe_client,
-            rate_limiter: Arc::new(RateLimiter::new(db)),
             executor,
             kinesis_client: if config.kinesis_access_key.is_some() {
                 build_kinesis_client(&config).await.log_err()