chore(ec2): remove c6gbd instance since it doesn't exist and cleanup …

…other instance types for the sake of consistency (#23145)

Remove `c6gbd` instance since it doesn't exist and cleanup other instance types for the sake of consistency.

----

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allowed-breaking-changes.txt

@@ -148,3 +148,5 @@ incompatible-argument:@aws-cdk/aws-route53-targets.InterfaceVpcEndpointTarget.<i
 # to allow the CLI to skip validating the bootstrap stack when the stack is not needed
 changed-type:@aws-cdk/cx-api.AssetManifestArtifact.requiresBootstrapStackVersion
 
+# removed mistyped ec2 instance class
+removed:aws-cdk-lib.aws_ec2.InstanceClass.COMPUTE6_GRAVITON2_HIGH_NETWORK_BANDWITH

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

@@ -421,7 +421,7 @@ export enum InstanceClass {
   /**
    * Compute optimized instances for high performance computing, 7th generation with Graviton3 processors
    */
-  COMPUTE7_GRAVITON3 = 'compute7_graviton3',
+  COMPUTE7_GRAVITON3 = 'compute7-graviton3',
 
   /**
    * Compute optimized instances for high performance computing, 7th generation with Graviton3 processors
@@ -440,12 +440,6 @@ export enum InstanceClass {
    */
   C6GD = 'c6gd',
 
-  /**
-   * Compute optimized instances for high performance computing, 6th generation with Graviton2 processors
-   * and high network bandwidth capabilities
-   */
-  COMPUTE6_GRAVITON2_HIGH_NETWORK_BANDWITH = 'compute6-graviton2-high-network-banwidth',
-
   /**
    * Compute optimized instances for high performance computing, 6th generation with Graviton2 processors
    * and high network bandwidth capabilities
@@ -1135,11 +1129,10 @@ export class InstanceType {
       [InstanceClass.C6G]: 'c6g',
       [InstanceClass.COMPUTE6_GRAVITON2_NVME_DRIVE]: 'c6gd',
       [InstanceClass.C6GD]: 'c6gd',
-      [InstanceClass.COMPUTE6_GRAVITON2_HIGH_NETWORK_BANDWIDTH]: 'c6gdb',
-      [InstanceClass.COMPUTE6_GRAVITON2_HIGH_NETWORK_BANDWITH]: 'c6gdb',
+      [InstanceClass.COMPUTE6_GRAVITON2_HIGH_NETWORK_BANDWIDTH]: 'c6gn',
+      [InstanceClass.C6GN]: 'c6gn',
       [InstanceClass.COMPUTE7_GRAVITON3]: 'c7g',
       [InstanceClass.C7G]: 'c7g',
-      [InstanceClass.C6GN]: 'c6gn',
       [InstanceClass.STORAGE2]: 'd2',
       [InstanceClass.D2]: 'd2',
       [InstanceClass.STORAGE3]: 'd3',