Correct 2024.5 warning and error

[ADHDSquir]

As of HA 2024.5, the following two issues appear in the Home Assistant log:

WARNING (ImportExecutor_0) [homeassistant.helpers.typing] ServiceCallType was used from stream_assist, this is a deprecated alias which will be removed in HA Core 2025.5. Use homeassistant.core.ServiceCall instead, please report it to the author of the 'stream_assist' custom integration

RuntimeError: Detected that custom integration 'stream_assist' calls async_write_ha_state from a thread at custom_components/stream_assist/sensor.py, line 47: self.async_write_ha_state(). Please report it to the author of the 'stream_assist' custom integration.

This PR updates these two items to the latest standard.