fix(firebaseai): remove candidateCount from LiveGenerationConfig since the connection fails silently when it is set (#17647)

Author: cynthiajoan

packages/firebase_ai/firebase_ai/lib/src/live_api.dart

@@ -77,7 +77,6 @@ final class LiveGenerationConfig extends BaseGenerationConfig {
  LiveGenerationConfig({
  this.speechConfig,
  super.responseModalities,
- super.candidateCount,
  super.maxOutputTokens,
  super.temperature,
  super.topP,

packages/firebase_ai/firebase_ai/test/live_test.dart

@@ -43,15 +43,13 @@ void main() {
  final liveGenerationConfig = LiveGenerationConfig(
  speechConfig: SpeechConfig(voiceName: 'Charon'),
  responseModalities: [ResponseModalities.text, ResponseModalities.audio],
- candidateCount: 2,
  maxOutputTokens: 100,
  temperature: 0.8,
  topP: 0.95,
  topK: 40,
  );
 
  expect(liveGenerationConfig.toJson(), {
- 'candidateCount': 2,
  'maxOutputTokens': 100,
  'temperature': 0.8,
  'topP': 0.95,

packages/firebase_vertexai/firebase_vertexai/test/live_test.dart

@@ -44,15 +44,13 @@ void main() {
  final liveGenerationConfig = LiveGenerationConfig(
  speechConfig: SpeechConfig(voiceName: 'Charon'),
  responseModalities: [ResponseModalities.text, ResponseModalities.audio],
- candidateCount: 2,
  maxOutputTokens: 100,
  temperature: 0.8,
  topP: 0.95,
  topK: 40,
  );
 
  expect(liveGenerationConfig.toJson(), {
- 'candidateCount': 2,
  'maxOutputTokens': 100,
  'temperature': 0.8,
  'topP': 0.95,