Added support for passing in a ToolsSchema in lieu of a list of provider-specific dicts when initializing OpenAIRealtimeLLMService.

I chose to go the somewhat hacky route of adding the `ToolsSchema` support into the `events.SessionProperties` model itself—even though we should never serialize that type when creating events—because the alternative seemed to be to create a new type for `OpenAIRealtimeLLMService` initialization parameters and then we'd have to contend with backward compatibility, which seemed like a bigger headache.

CHANGELOG.md

@@ -9,6 +9,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Added support for passing in a `ToolsSchem` in lieu of a list of provider-
+  specific dicts when initializing `OpenAIRealtimeLLMService`.
+
 - Added `TransportParams.audio_out_silence_secs`, which specifies how many
   seconds of silence to output when an `EndFrame` reaches the output
   transport. This can help ensure that all audio data is fully delivered to