aws_cognito: UserPoolIdentityProviderOidc doesn't support SecretValue for client secret

### Describe the feature

Hello,

Small FR that would make the use of SecretValue more straightforward.

`UserPoolIdentityProviderOidc` needs a client secret value for deployment. As of now it only supports `string` value.
Compared to the generic one like `UserPoolIdentityProviderGoogle` who support `clientSecretValue`.

### Use Case

It would make the DX a bit better, simplifying the resolution. And also align with the other providers from the cognito package.

### Proposed Solution

_No response_

### Other Information

_No response_

### Acknowledgements

- [X] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### CDK version used

2.131.0

### Environment details (OS name and version, etc.)

MacOS

Start with UserPoolIdentityProviderOidc in the Cognito package and compare its client secret handling with UserPoolIdentityProviderGoogle, which already supports clientSecretValue. The work is complete when the OIDC provider accepts SecretValue consistently with the comparable provider and the relevant Cognito behavior is covered by tests.

Written by the indexing model from the issue text.