Add default device class display precision for Sensor (#145013)

* Add default device class display precision for Sensor

* Renaming, docstrings, cleanup

* Simplify units list

* Fix tests

* Fix missing precision when suggested is specified

* Update snapshots

* Fix when unit of measurement is not valid

* Fix tests

* Fix deprecated unit usage

* Fix goalzero tests

The sensor native_value method was accessing the data dict and trowing,
since the mock did not have any data for the sensors.

Since now the precision is always specified (it was missing for those
sensors), the throw was hitting async_update_entity_options in _update_suggested_precision.
Previously, async_update_entity_options was not called since it had no
precision.

* Fix metoffice

* Fix smartthings

* Add default sensor data for Tesla Wall Connector tests

* Update snapshots

* Revert spaces

* Update smartthings snapshots

* Add missing sensor mock for tesla wall connector

* Address review comments

* Add doc comment

* Add cap to doc comment

* Update comment

* Update snapshots

* Update comment

tests/common.py

@@ -1959,3 +1959,28 @@ def get_schema_suggested_value(schema: vol.Schema, key: str) -> Any | None:
                 return None
             return schema_key.description["suggested_value"]
     return None
+
+
+def get_sensor_display_state(
+    hass: HomeAssistant, entity_registry: er.EntityRegistry, entity_id: str
+) -> str:
+    """Return the state rounded for presentation."""
+    state = hass.states.get(entity_id)
+    assert state
+    value = state.state
+
+    entity_entry = entity_registry.async_get(entity_id)
+    if entity_entry is None:
+        return value
+
+    if (
+        precision := entity_entry.options.get("sensor", {}).get(
+            "suggested_display_precision"
+        )
+    ) is None:
+        return value
+
+    with suppress(TypeError, ValueError):
+        numerical_value = float(value)
+        value = f"{numerical_value:z.{precision}f}"
+    return value