Fix: Update PhotoReasoningScreen previews with notification dialog params

The `PhotoReasoningScreen` composable was updated to accept
`showNotificationRationaleDialog` and `onShowNotificationRationaleDialogChange`
parameters due to state hoisting. The `@Preview` functions
(`PhotoReasoningScreenPreviewWithContent` and `PhotoReasoningScreenPreviewEmpty`)
were not updated accordingly, leading to "No value passed for parameter"
compilation errors.

This commit updates both preview functions to pass default values
(`showNotificationRationaleDialog = false`, `onShowNotificationRationaleDialogChange = {}`)
for these new parameters, resolving the build errors.

Author: google-labs-jules[bot]

app/src/main/kotlin/com/google/ai/sample/feature/multimodal/PhotoReasoningScreen.kt

@@ -1062,7 +1062,9 @@ fun PhotoReasoningScreenPreviewWithContent() {
                 PhotoReasoningMessage(text = "I am here to help you. What do you want to know?", participant = PhotoParticipant.MODEL)
             ),
             isKeyboardOpen = false,
-            onStopClicked = {}
+            onStopClicked = {},
+            showNotificationRationaleDialog = false,
+            onShowNotificationRationaleDialogChange = {}
         )
     }
 }
@@ -1160,7 +1162,14 @@ val SystemMessageEntrySaver = Saver<SystemMessageEntry?, List<String?>>(
 @Composable
 @Preview(showSystemUi = true)
 fun PhotoReasoningScreenPreviewEmpty() {
-    MaterialTheme { PhotoReasoningScreen(isKeyboardOpen = false, onStopClicked = {}) }
+    MaterialTheme {
+        PhotoReasoningScreen(
+            isKeyboardOpen = false,
+            onStopClicked = {},
+            showNotificationRationaleDialog = false,
+            onShowNotificationRationaleDialogChange = {}
+        )
+    }
 }
 
 @Preview(showBackground = true)