refactor: use gemini-2.5 models for the Gemini Live quickstart

Author: thatfiredev

firebase-ai/app/src/main/java/com/google/firebase/quickstart/ai/FirebaseAISamples.kt

@@ -275,8 +275,6 @@ val FIREBASE_AI_SAMPLES = listOf(
         description = "Use bidirectional streaming to get information about" +
                 " weather conditions for a specific US city on a specific date",
         navRoute = "stream",
-        backend = GenerativeBackend.vertexAI(),
-        modelName = "gemini-2.0-flash-live-preview-04-09",
         categories = listOf(Category.LIVE_API, Category.AUDIO, Category.FUNCTION_CALLING),
         tools = listOf(
             Tool.functionDeclarations(
@@ -305,8 +303,6 @@ val FIREBASE_AI_SAMPLES = listOf(
         description = "Use bidirectional streaming to chat with Gemini using your" +
                 " phone's camera",
         navRoute = "streamVideo",
-        backend = GenerativeBackend.vertexAI(),
-        modelName = "gemini-2.0-flash-live-preview-04-09",
         categories = listOf(Category.LIVE_API, Category.VIDEO, Category.FUNCTION_CALLING),
         tools = listOf(
             Tool.functionDeclarations(

firebase-ai/app/src/main/java/com/google/firebase/quickstart/ai/feature/live/BidiViewModel.kt

@@ -41,11 +41,17 @@ class BidiViewModel(savedStateHandle: SavedStateHandle) : ViewModel() {
             responseModality = ResponseModality.AUDIO
         }
 
+        val defaultModelName = if (sample.backend == GenerativeBackend.googleAI()) {
+          "gemini-2.5-flash-native-audio-preview-09-2025"
+        } else {
+          "gemini-live-2.5-flash-preview-native-audio-09-2025"
+        }
+
         @OptIn(PublicPreviewAPI::class)
         val liveModel =
             FirebaseAI.getInstance(Firebase.app, sample.backend)
                 .liveModel(
-                    modelName = sample.modelName ?: "gemini-live-2.5-flash",
+                    modelName = sample.modelName ?: defaultModelName,
                     generationConfig = liveGenerationConfig,
                     tools = sample.tools,
                 )