feat(firebaseai): mark imagen generate function ga (#17757)

* mark imagen generate function ga

* fix analyzer

Author: cynthiajoan

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

@@ -17,7 +17,6 @@ import 'package:firebase_auth/firebase_auth.dart';
 import 'package:firebase_core/firebase_core.dart';
 import 'package:firebase_core_platform_interface/firebase_core_platform_interface.dart'
     show FirebasePluginPlatform;
-import 'package:meta/meta.dart';
 
 import '../firebase_ai.dart';
 import 'base_model.dart';
@@ -158,7 +157,6 @@ class FirebaseAI extends FirebasePluginPlatform {
   ///
   /// The optional [safetySettings] can be used to control and guide the
   /// generation. See [ImagenSafetySettings] for details.
-  @experimental
   ImagenModel imagenModel(
       {required String model,
       ImagenGenerationConfig? generationConfig,

packages/firebase_ai/firebase_ai/lib/src/imagen/imagen_api.dart

@@ -13,12 +13,9 @@
 // limitations under the License.
 import 'dart:developer';
 
-import 'package:meta/meta.dart';
-
 /// Specifies the level of safety filtering for image generation.
 ///
 /// If not specified, default will be "block_medium_and_above".
-@experimental
 enum ImagenSafetyFilterLevel {
   /// Strongest filtering level, most strict blocking.
   blockLowAndAbove('block_low_and_above'),
@@ -60,7 +57,6 @@ enum ImagenSafetyFilterLevel {
 /// Allow generation of people by the model.
 ///
 /// If not specified, the default value is "allow_adult".
-@experimental
 enum ImagenPersonFilterLevel {
   /// Disallow the inclusion of people or faces in images.
   blockAll('dont_allow'),
@@ -96,7 +92,6 @@ enum ImagenPersonFilterLevel {
 /// A class representing safety settings for image generation.
 ///
 /// It includes a safety filter level and a person filter level.
-@experimental
 final class ImagenSafetySettings {
   // ignore: public_member_api_docs
   ImagenSafetySettings(this.safetyFilterLevel, this.personFilterLevel);
@@ -119,7 +114,6 @@ final class ImagenSafetySettings {
 /// The aspect ratio for the image.
 ///
 /// The default value is "1:1".
-@experimental
 enum ImagenAspectRatio {
   /// Square (1:1).
   square1x1('1:1'),
@@ -161,7 +155,6 @@ enum ImagenAspectRatio {
 }
 
 /// Configuration options for image generation.
-@experimental
 final class ImagenGenerationConfig {
   // ignore: public_member_api_docs
   ImagenGenerationConfig(
@@ -202,7 +195,6 @@ final class ImagenGenerationConfig {
 }
 
 /// Represents the image format and compression quality.
-@experimental
 final class ImagenFormat {
   // ignore: public_member_api_docs
   ImagenFormat(this.mimeType, this.compressionQuality);

packages/firebase_ai/firebase_ai/lib/src/imagen/imagen_content.dart

@@ -13,7 +13,6 @@
 // limitations under the License.
 import 'dart:convert';
 import 'dart:typed_data';
-import 'package:meta/meta.dart';
 import '../error.dart';
 
 /// Base type of Imagen Image.
@@ -29,7 +28,6 @@ sealed class ImagenImage {
 }
 
 /// Represents an image stored as a base64-encoded string.
-@experimental
 final class ImagenInlineImage implements ImagenImage {
   // ignore: public_member_api_docs
   ImagenInlineImage({

packages/firebase_ai/firebase_ai/lib/src/imagen/imagen_model.dart

@@ -24,7 +24,6 @@ part of '../base_model.dart';
 /// > Warning: For Vertex AI in Firebase, image generation using Imagen 3 models
 /// is in Public Preview, which means that the feature is not subject to any SLA
 /// or deprecation policy and could change in backwards-incompatible ways.
-@experimental
 final class ImagenModel extends BaseApiClientModel {
   ImagenModel._(
       {required FirebaseApp app,
@@ -84,7 +83,6 @@ final class ImagenModel extends BaseApiClientModel {
 
   /// Generates images with format of [ImagenInlineImage] based on the given
   /// prompt.
-  @experimental
   Future<ImagenGenerationResponse<ImagenInlineImage>> generateImages(
     String prompt,
   ) =>
@@ -194,7 +192,6 @@ final class ImagenModel extends BaseApiClientModel {
 }
 
 /// Returns a [ImagenModel] using it's private constructor.
-@experimental
 ImagenModel createImagenModel({
   required FirebaseApp app,
   required String location,