feat: Add ErrorFrame emission to TTS/STT services for pipeline error detection (#2881)

* feat: Add ErrorFrame emission to TTS/STT services for pipeline error detection

- Add ErrorFrame emission to all major TTS/STT services during initialization and runtime failures
- Services updated: Cartesia, ElevenLabs, Deepgram, AssemblyAI, Rime, Azure
- ErrorFrame objects emitted with fatal=False for graceful degradation
- Enables on_pipeline_error event handler to detect service failures programmatically
- Add comprehensive pytest test suite to verify ErrorFrame emission
- Fixes issue where services failed gracefully but didn't emit ErrorFrame objects

This allows developers to implement real-time error monitoring and alerting
using the on_pipeline_error event handler introduced in v0.0.90.

* Update STT and TTS services to use consistent error handling pattern

- Improves error handling consistency across all services

* Add changelog entry for STT/TTS error handling improvements

* Linting issues Resolved

* Azure STT ErrorFrames added with consistent patterns

* Cartesia STT and Deepgram STT; additional fixes made

* Removed Fatal Flags across services, removed duplication

* Moving the changelog entry to the correct place.

* Refactoring some classes to use yield instead of push_error directly.

* Fixing ruff format.

---------

Co-authored-by: Filipi Fuchter <filipi87@gmail.com>

CHANGELOG.md

@@ -18,6 +18,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Updated all STT and TTS services to use consistent error handling pattern with
+  `push_error()` method for better pipeline error event integration.
+
 - Added Hindi support for Rime TTS services.
 
 - Updated `GeminiTTSService` to use Google Cloud Text-to-Speech streaming API