feat: text-to-speech x LLM integration

[IgorSwat]

Description

This pull request introduces a few changes to the Text-to-Speech module:

• Improved streaming mode by allowing an incrementally expanded text input. This change focuses on integrating T2S with text generation models (e.g. Llama 3.2).
• Added simple test cases for T2S module.

Introduces a breaking change?

• Yes
• No

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update (improves or adds clarity to existing documentation)
• Other (chores, tests, code style improvements etc.)

Tested on

• iOS
• Android

Testing instructions

To test the Text-to-Speech module, run the set of tests for this module.
To test the new streaming mode and it's integration with text generation models, one can use 'text-to-speech-llm' demo app.

Screenshots

Related issues

#773
#897

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes