eks: TaintEffect Enum has unsupported values

### Describe the bug

When trying to use the [TaintEffect Enum](https://github.com/aws/aws-cdk/blob/v2.202.0/packages/aws-cdk-lib/aws-eks/lib/managed-nodegroup.ts#L160) for a kubernetes manifest describing a Karpenter `NodePool`, the string value is all uppercase and does not seem to match what a taint is as a string in [k8s docs](https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/) so the validation fails. This however does work for k8s nodegroups.

From the [python docs](https://docs.aws.amazon.com/cdk/api/v2/python/aws_cdk.aws_eks/TaintEffect.html) it looks like the python lib uses the proper values for the `TaintEffect` Enum. I am not sure why that is, if TS is the source.

As a workaround I would need to specify it as a string and not use the `TaintSpec` interface or `TaintEffect` enum when using the TypeScript lib.

When using CDK to create a Karpenter nodepool manifest in the eks cluster I am seeing this error:
`Error: b'The NodePool "default-nodepool" is invalid: \n* spec.template.spec.taints[0].effect: Unsupported value: "NO_EXECUTE": supported values: "NoSchedule", "PreferNoSchedule", "NoExecute"\n*`

(P.S. Prompted a song for fun: https://suno.com/s/8JD1CY0RmFeOjSBJ)

### Regression Issue

- [ ] Select this option if this issue appears to be a regression.

### Last Known Working CDK Library Version

N/A

### Expected Behavior

I expect to not have an error when using the `TaintEffect` enum to configure a karpenter nodepool manifest with the NoExecute taint.

### Current Behavior

`| Custom::AWSCDK-EKS-KubernetesResource | rKarpenter/rNodeClass-default-nodeclass/rNodePool-default-nodepool/rNodePool-default-nodepool/Resource/Default (rKarpenterrNodeClassdefaultnodeclassrNodePooldefaultnodepoolDC25F7A7) Received response status [FAILED] from custom resource. Message returned: Error: b'The NodePool "default-nodepool" is invalid: \n* spec.template.spec.taints[0].effect: Unsupported value: "NO_EXECUTE": supported values: "NoSchedule", "PreferNoSchedule", "NoExecute"\n* : Invalid value: "null": some validation rules were not checked because the object was invalid; correct the existing errors to complete validation\n'`

### Reproduction Steps

I believe this is a short enough example that can explain what I am trying to accomplish and be copied and reused. However if you need a larger, more complete, example I can try to work on a sample test stack and upload it to a public repo.

```typescript
import { Nodegroup, KubernetesManifest, TaintEffect, TaintSpec } from 'aws-cdk-lib/aws-eks';

const ciliumTaint: TaintSpec = {
key: 'node.cilium.io/agent-not-ready',
value: 'true',
effect: TaintEffect.NO_EXECUTE
}

// NodeGroups
const nodeGroup = new Nodegroup(this, id, {
cluster: cluster,
subnets: subnets,
taints: [ciliumTaint]
};
}

// NodePool
const chart = new KubernetesManifest(this, id, {
cluster: cluster,
manifest: [{
apiVersion: `karpenter.sh/${apiVersion}`,
kind: 'NodePool',
metadata: {
name: name
},
spec: {
template: {
spec: {
taints: [ciliumTaint]
}
}
}
}]
});
```

### Possible Solution

Update the enum to match k8s taint values.
```typescript
export enum TaintEffect {
/**
* NoSchedule
*/
NO_SCHEDULE = 'NoSchedule',
/**
* PreferNoSchedule
*/
PREFER_NO_SCHEDULE = 'PreferNoSchedule',
/**
* NoExecute
*/
NO_EXECUTE = 'NoExecute',
}
```

### Additional Information/Context

EKS Version: 1.32
Cilium Version: 1.17.2
Karpenter-crd Version: 1.5.1
Karpenter Version: 1.5.1

Addons:
- addonName: coredns
addonVersion: v1.11.4-eksbuild.2
preserveOnDelete: false
- addonName: aws-ebs-csi-driver
addonVersion: v1.41.0-eksbuild.1
preserveOnDelete: false
- addonName: aws-mountpoint-s3-csi-driver
addonVersion: v1.13.0-eksbuild.1
preserveOnDelete: false

### AWS CDK Library version (aws-cdk-lib)

aws-cdk-lib@2.195.0

### AWS CDK CLI version

2.1016.0 (build 66e0b2d)

### Node.js Version

v22.13.1

### OS

Windows 10 22H2 (19045.3930)

### Language

TypeScript

### Language Version

5.8.3

### Other information

_No response_

Start in packages/aws-cdk-lib/aws-eks/lib/managed-nodegroup.ts around the TaintEffect enum referenced in the issue, then reproduce the KubernetesManifest example with a Karpenter NodePool. Done means the enum values serialize as NoSchedule, PreferNoSchedule, and NoExecute so the manifest passes Kubernetes validation.

Written by the indexing model from the issue text.