Always setup demo platforms with device support from config entry (#94586)

* Always setup demo platforms with device support from config entry

* Adjust test fixutres

* Update tests depending on the demo integration

tests/components/camera/conftest.py

@@ -5,6 +5,7 @@ import pytest
 
 from homeassistant.components import camera
 from homeassistant.components.camera.const import StreamType
+from homeassistant.const import Platform
 from homeassistant.core import HomeAssistant
 from homeassistant.setup import async_setup_component
 
@@ -17,6 +18,16 @@ async def setup_homeassistant(hass: HomeAssistant):
     await async_setup_component(hass, "homeassistant", {})
 
 
+@pytest.fixture(autouse=True)
+async def camera_only() -> None:
+    """Enable only the camera platform."""
+    with patch(
+        "homeassistant.components.demo.COMPONENTS_WITH_CONFIG_ENTRY_DEMO_PLATFORM",
+        [Platform.CAMERA],
+    ):
+        yield
+
+
 @pytest.fixture(name="mock_camera")
 async def mock_camera_fixture(hass):
     """Initialize a demo camera platform."""