core: Playing camera stream using google assistant is broken in 0.115

The problem

Can no longer play camera stream on google home hub using the google assistant integration. For example, “Hey google, show me the front door camera” no longer works.

Environment

• Home Assistant Core release with the issue: 0.115.0 onwards
• Last working Home Assistant Core release (if known): 0.114.0
• Operating environment (OS/Container/Supervised/Core): Supervised
• Integration causing this issue: google_assistant
• Link to integration documentation on our website: https://www.home-assistant.io/integrations/google_assistant/

Problem-relevant configuration.yaml

google_assistant:
  project_id: hassio-XXXX
  service_account: !include service_account.json
  exposed_domains:
    - stream
    - camera
    - switch
    - light
    - scene
  entity_config: 
    ... (trimmed for clarity)

Traceback/Error logs

No errors in log.

Additional information

Some changes were made to cast/stream to fix a similar issue (#40376) that occurred after the addition of audio to the streams. @hunterjm has indicated that the google_assistant integration will likely need to update the parameters of the Camera Trait. Related code is here: https://github.com/home-assistant/core/blob/dev/homeassistant/components/google_assistant/trait.py#L253-L290