Use load_json_object in fitbit (#88585)

* Use load_json_object in fitbit

* Remove unnecessary cast

homeassistant/components/fitbit/sensor.py

@@ -27,7 +27,7 @@ from homeassistant.helpers.icon import icon_for_battery_level
 from homeassistant.helpers.json import save_json
 from homeassistant.helpers.network import NoURLAvailableError, get_url
 from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
-from homeassistant.util.json import load_json
+from homeassistant.util.json import load_json_object
 from homeassistant.util.unit_system import METRIC_SYSTEM
 
 from .const import (
@@ -85,7 +85,7 @@ def request_app_setup(
         """Handle configuration updates."""
         config_path = hass.config.path(FITBIT_CONFIG_FILE)
         if os.path.isfile(config_path):
-            config_file = load_json(config_path)
+            config_file = load_json_object(config_path)
             if config_file == DEFAULT_CONFIG:
                 error_msg = (
                     f"You didn't correctly modify {FITBIT_CONFIG_FILE}, please try"
@@ -161,7 +161,7 @@ def setup_platform(
     """Set up the Fitbit sensor."""
     config_path = hass.config.path(FITBIT_CONFIG_FILE)
     if os.path.isfile(config_path):
-        config_file: ConfigType = cast(ConfigType, load_json(config_path))
+        config_file = load_json_object(config_path)
         if config_file == DEFAULT_CONFIG:
             request_app_setup(
                 hass, config, add_entities, config_path, discovery_info=None
@@ -175,13 +175,10 @@ def setup_platform(
     if "fitbit" in _CONFIGURING:
         configurator.request_done(hass, _CONFIGURING.pop("fitbit"))
 
-    access_token: str | None = config_file.get(ATTR_ACCESS_TOKEN)
-    refresh_token: str | None = config_file.get(ATTR_REFRESH_TOKEN)
-    expires_at: int | None = config_file.get(ATTR_LAST_SAVED_AT)
     if (
-        access_token is not None
-        and refresh_token is not None
-        and expires_at is not None
+        (access_token := config_file.get(ATTR_ACCESS_TOKEN)) is not None
+        and (refresh_token := config_file.get(ATTR_REFRESH_TOKEN)) is not None
+        and (expires_at := config_file.get(ATTR_LAST_SAVED_AT)) is not None
     ):
         authd_client = Fitbit(
             config_file.get(CONF_CLIENT_ID),
@@ -192,7 +189,7 @@ def setup_platform(
             refresh_cb=lambda x: None,
         )
 
-        if int(time.time()) - expires_at > 3600:
+        if int(time.time()) - cast(int, expires_at) > 3600:
             authd_client.client.refresh_token()
 
         user_profile = authd_client.user_profile_get()["user"]