Pass up intent with completion requests (#31710)

This PR adds a new `intent` field to completion requests to assist in
categorizing them correctly.

Release Notes:

- N/A

---------

Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>

crates/rules_library/src/rules_library.rs

@@ -923,6 +923,7 @@ impl RulesLibrary {
                                 LanguageModelRequest {
                                     thread_id: None,
                                     prompt_id: None,
+                                    intent: None,
                                     mode: None,
                                     messages: vec![LanguageModelRequestMessage {
                                         role: Role::System,