Use single_instance_allowed in hassio (#128060)

* use single_instance_allowed

* mark hassio as `single_config_entry`

homeassistant/components/hassio/config_flow.py

@@ -18,7 +18,4 @@ class HassIoConfigFlow(ConfigFlow, domain=DOMAIN):
         self, user_input: dict[str, Any] | None = None
     ) -> ConfigFlowResult:
         """Handle the initial step."""
-        # We only need one Hass.io config entry
-        await self.async_set_unique_id(DOMAIN)
-        self._abort_if_unique_id_configured()
         return self.async_create_entry(title="Supervisor", data={})

homeassistant/components/hassio/manifest.json

@@ -6,5 +6,6 @@
   "documentation": "https://www.home-assistant.io/integrations/hassio",
   "iot_class": "local_polling",
   "quality_scale": "internal",
-  "requirements": ["aiohasupervisor==0.2.0b0"]
+  "requirements": ["aiohasupervisor==0.2.0b0"],
+  "single_config_entry": true
 }

homeassistant/generated/integrations.json

@@ -2470,7 +2470,8 @@
       "name": "Home Assistant Supervisor",
       "integration_type": "hub",
       "config_flow": false,
-      "iot_class": "local_polling"
+      "iot_class": "local_polling",
+      "single_config_entry": true
     },
     "havana_shade": {
       "name": "Havana Shade",

tests/components/hassio/test_config_flow.py

@@ -38,4 +38,4 @@ async def test_multiple_entries(hass: HomeAssistant) -> None:
         DOMAIN, context={"source": "system"}
     )
     assert result["type"] is FlowResultType.ABORT
-    assert result["reason"] == "already_configured"
+    assert result["reason"] == "single_instance_allowed"