Fixing the api_streams sensor (#22200)

* Fire events with websocket messages.

* Added tests to validate

* Fixed api_streams sensor to use new sensor

* Delete from coverageac as now works.

* Removed websocket request event.

* Use dispatcher instead of events.

* Moved sensor to under websocket_api

* Changes as per code review

* Fixed tests.

* Modified test

* Patch

homeassistant/components/websocket_api/http.py

@@ -13,7 +13,9 @@ from homeassistant.core import callback
 from homeassistant.components.http import HomeAssistantView
 from homeassistant.helpers.json import JSONEncoder
 
-from .const import MAX_PENDING_MSG, CANCELLATION_ERRORS, URL, ERR_UNKNOWN_ERROR
+from .const import (
+    MAX_PENDING_MSG, CANCELLATION_ERRORS, URL, ERR_UNKNOWN_ERROR,
+    SIGNAL_WEBSOCKET_CONNECTED, SIGNAL_WEBSOCKET_DISCONNECTED)
 from .auth import AuthPhase, auth_required_message
 from .error import Disconnect
 from .messages import error_message
@@ -142,6 +144,8 @@ class WebSocketHandler:
 
             self._logger.debug("Received %s", msg)
             connection = await auth.async_handle(msg)
+            self.hass.helpers.dispatcher.async_dispatcher_send(
+                SIGNAL_WEBSOCKET_CONNECTED)
 
             # Command phase
             while not wsock.closed:
@@ -192,4 +196,7 @@ class WebSocketHandler:
             else:
                 self._logger.warning("Disconnected: %s", disconnect_warn)
 
+            self.hass.helpers.dispatcher.async_dispatcher_send(
+                SIGNAL_WEBSOCKET_DISCONNECTED)
+
         return wsock