Google Assistant SDK: TTS for response playback

[tronikos]

Proposed change

Support TTS in Google Assistant SDK to be able to playback Google Assistant's audio response.

Users will need to add:

tts:
  - platform: google_assistant_sdk

and then they can call:

service: tts.google_assistant_sdk_say
data:
  message: tell me a joke
  entity_id: media_player.living_room_speaker
  cache: false

Underlyging library changes:
tronikos/gassist_text@0.0.7...0.0.8

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Google Assistant SDK: Document audio response playback home-assistant.io#25653

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.
• Untested files have been added to .coveragerc.

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.

[allenporter]

I haven't reviewed a tts service before but it looks pretty straight forward. Great! 👍🏼

[tronikos]

A better alternative to this is #85989 since this isn't really TTS. It's more like text to answer’s speech.