MediaPackage: speke 2 configuration error

### Describe the bug

The speke 2 configuration "EncryptionContractConfiguration" is not correctly converted to the cloud formation template, giving an error when deploying.

### Expected Behavior

The cf template should include the speke 2 configurations and the deploy show set speke 2 configuration.

### Current Behavior

When generating a cmaf or dash mediapackage with the following information:

```
spekeKeyProvider: {
roleArn: "arn",
systemIds: "xxxxxxxxxxx",
url: "https://xxx.xx",
resourceId: `resource-cmaf`,
encryptionContractConfiguration: {
presetSpeke20Audio: "PRESET-AUDIO-1",
presetSpeke20Video: "PRESET-VIDEO-1",
},
},
```
the generated cloudformation template doesn't include the preset information:
```
"SpekeKeyProvider": {
"EncryptionContractConfiguration": {},
"ResourceId": "resource-xxxx",
"RoleArn": {
"Fn::ImportValue": "role"
},
"SystemIds": [
"xxxxx"
],
```
And when we deploy we get the following error:
```
Resource handler returned message: "Model validation failed (#: #: only 1 subschema matches out of 2)
#/CmafPackage/Encryption/SpekeKeyProvider/EncryptionContractConfiguration: 2 schema violations found (#/CmafPackage/Encryption/SpekeKeyProvider/EncryptionContractConfiguration)" (RequestToken: a53b01e3-b50a-3ce3-4cd8-6550561eda09, HandlerErrorCode: InvalidRequest)
```

### Reproduction Steps

Just create a media package endpoint with speke 2 configurations and check the generated cf template.

### Possible Solution

_No response_

### Additional Information/Context

_No response_

### CDK CLI Version

2.86.0 (build 1130fab)

### Framework Version

2.86

### Node.js Version

v18.16.0

### OS

windows 11

### Language

Typescript

### Language Version

5.1.6

### Other information

_No response_

Start with the TypeScript MediaPackage endpoint configuration using SpekeKeyProvider and generate its CloudFormation template. Compare the emitted EncryptionContractConfiguration with the supplied presetSpeke20Audio and presetSpeke20Video values, then verify that a deployment accepts the generated template and preserves the SPEKE 2 settings.

Written by the indexing model from the issue text.