use non-null assertions and optional chaining for authenticatedUser state handling

app/(tabs)/index.tsx

@@ -13,7 +13,7 @@ export default function HomeScreen() {
     const {theme} = useTheme();
 
     useEffect(() => {
-        setIdle(authenticatedUser?.lastState.global.mode === "idle")
+        setIdle(authenticatedUser!.lastState?.global.mode === "idle")
     }, [])
 
     return (

app/(tabs)/modes/text.tsx

@@ -9,7 +9,7 @@ import {View} from "react-native";
 
 export default function TextScreen() {
     const {authenticatedUser} = useAuth();
-    const [textProps, setTextProps] = useState(authenticatedUser?.lastState.text);
+    const [textProps, setTextProps] = useState(authenticatedUser!.lastState?.text);
 
     return (
         <ThemedBackground>
@@ -29,7 +29,7 @@ export default function TextScreen() {
 
                 <CustomColorPicker
                     onSelect={rgb => setTextProps(prev => ({ ...prev!, color: rgb }))}
-                    defaultColor={textProps!.color}
+                    defaultColor={textProps?.color}
                 />
             </View>