Fix shadow observer lifecycle, learning and prediction correctness

tests/test_weather_sources.py

@@ -66,6 +66,7 @@ class WeatherInputs(unittest.TestCase):
             self.assertIsNone(w.normalize("temperature", value, "°C"))
         self.assertIsNone(w.normalize("temperature", 22.0, "km/h"))
         self.assertIsNone(w.normalize("wind", -3, "m/s"))
+        self.assertIsNone(w.normalize("temperature", 20, 42))
         self.assertIsNone(w.normalize("clouds", 150, "%"))