chore(bedrock): support Titan Image Generator v2 (#31045)

Add new foundation model.

Ref:
* https://aws.amazon.com/about-aws/whats-new/2024/08/titan-image-generator-v2-amazon-bedrock/
* https://docs.aws.amazon.com/bedrock/latest/userguide/model-ids.html


### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/aws-cdk-lib/aws-bedrock/lib/foundation-model.ts

@@ -50,6 +50,9 @@ export class FoundationModelIdentifier {
   /** Base model "amazon.titan-image-generator-v1:0". */
   public static readonly AMAZON_TITAN_IMAGE_GENERATOR_V1_0 = new FoundationModelIdentifier('amazon.titan-image-generator-v1:0');
 
+  /** Base model "amazon.titan-image-generator-v2:0". */
+  public static readonly AMAZON_TITAN_IMAGE_GENERATOR_V2_0 = new FoundationModelIdentifier('amazon.titan-image-generator-v2:0');
+
   /** Base model "amazon.titan-embed-image-v1:0". */
   public static readonly AMAZON_TITAN_EMBED_IMAGE_V1_0 = new FoundationModelIdentifier('amazon.titan-embed-image-v1:0');