Introduce LanguageModelToolUse::raw_input (#29322)

This is to enable alternative streaming solutions at the application
layer. I'm not sure we really should have performed parsing of the input
at this layer. Either way I want to experiment with streaming approaches
in a separate crate on a branch, and this will help.

/cc @maxdeviant @bennetbo @rtfeldman

Closes #ISSUE

Release Notes:

- N/A

crates/language_models/src/provider/bedrock.rs

@@ -894,6 +894,7 @@ pub fn map_to_language_model_completion_events(
                                                 id: tool_use.id.into(),
                                                 name: tool_use.name.into(),
                                                 is_input_complete: true,
+                                                raw_input: tool_use.input_json.clone(),
                                                 input: if tool_use.input_json.is_empty() {
                                                     Value::Null
                                                 } else {