collab: Include more information on some LLM usage log lines (#28116)

This PR updates the `user rate limit` and `user usage` log lines to
include some more information that will be useful for graphing in Axiom.

Release Notes:

- N/A

crates/collab/src/llm.rs

@@ -574,6 +574,7 @@ async fn check_usage_limit(
                 is_staff = claims.is_staff,
                 provider = provider.to_string(),
                 model = model.name,
+                usage_measure = resource,
                 requests_this_minute = usage.requests_this_minute,
                 tokens_this_minute = usage.tokens_this_minute,
                 input_tokens_this_minute = usage.input_tokens_this_minute,
@@ -696,6 +697,8 @@ impl<S> Drop for TokenCountingStream<S> {
                     login = claims.github_user_login,
                     authn.jti = claims.jti,
                     is_staff = claims.is_staff,
+                    provider = provider.to_string(),
+                    model = model,
                     requests_this_minute = usage.requests_this_minute,
                     tokens_this_minute = usage.tokens_this_minute,
                     input_tokens_this_minute = usage.input_tokens_this_minute,