chore(ec2): support G6e instance type (#31134)

Add G6e instance type.

Ref: https://aws.amazon.com/about-aws/whats-new/2024/08/amazon-ec2-g6e-instances/

### 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)

----

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

Author: mazyu36

packages/aws-cdk-lib/aws-ec2/lib/instance-types.ts

@@ -900,6 +900,16 @@ export enum InstanceClass {
    */
   G6 = 'g6',
 
+  /**
+   * Cost-efficient GPU-based instances for AI inference and spatial computing workloads, 6th generation
+   */
+  GRAPHICS6_EFFICIENT = 'graphics6-efficient',
+
+  /**
+   * Cost-efficient GPU-based instances for AI inference and spatial computing workloads, 6th generation
+   */
+  G6E = 'g6e',
+
   /**
    * Parallel-processing optimized instances, 2nd generation
    */
@@ -1590,6 +1600,8 @@ export class InstanceType {
       [InstanceClass.G5G]: 'g5g',
       [InstanceClass.GRAPHICS6]: 'g6',
       [InstanceClass.G6]: 'g6',
+      [InstanceClass.GRAPHICS6_EFFICIENT]: 'g6e',
+      [InstanceClass.G6E]: 'g6e',
       [InstanceClass.PARALLEL2]: 'p2',
       [InstanceClass.P2]: 'p2',
       [InstanceClass.PARALLEL3]: 'p3',