Optimize api calls between envoy_reader and Home Assistant (#42857)

* Updating sensor to use single API call

* Updated comment

Updated comment to reflect that polling is needed.

* Reduced calls to single API call

* Added except handling and increased async timeout

* Cleaned up some comments

* Added error handling

* Added last_reported date for inverters

* Added message during failed update

* Added retries to update function

* Updated update function

* Reformatted sensor.py with black

* Increased default scan period

* fixed timedelta typo

* importing CoordinatorEntity

* Check during setup else raise PlatformNotReady

* Removed async_update and override state

* using SCAN_INTERVAL constant

* fixed typo

* removed unused constant

* Removed retry logic

* Changed to catching exceptions rather than strings

* shortened string split line

* Replace requests_async with httpx

* Bump envoy_reader version to 0.17.2

* Resolving comments from PR requested changes

* Fixed typo in scan_interval

* Removed period from logging messages

* Bumping envoy_reader to 0.18.0

* Incorporating suggested changes

* Removing no longer used try/except

* Fail setup if authentication fails

* Bump envoy_reader to 0.18.2