Mashup API error response data is missing

[hdoedens]

Describe the bug
When a call to PCore.getMashupApi().createCase() fails, there are no error details available in the catch property. The response data is missing.

To Reproduce
Steps to reproduce the behavior:

1. Create a case type with a Validation in the requirements section of the first stage, failing the validation with an error like 'creation failed'.
2. Open a browser and navigate to the portal with developer network tools open.
3. From a constellation portal, execute the following code

PCore.getMashupApi().createCase(option.pyClassName, contextName, {
  pageName: 'pyEmbedAssignment',
  startingFields: startingFields as object,
}).catch(response => {
  console.log({response})
});

4. Check the network response -> HTTP 422 with the error message 'creation failed'
5. Check the console log -> response: undefined

Expected behavior
I would expect to have the error response available in the catch block for further processing.

Desktop (please complete the following information):

• OS: MacOS Sonoma
• Browser: all browsers (I used Chrome)

Additional context
The HTTP error is written to the redux store, but there seems no API call to retrieve it using the Constellation SDK.

{
  data: {
    app: {
      context_data: {
        isLoading: false,
        caseInfo: {
          content: {
            summary_of_messages__: {
              propertyMessages__: {}
            }
          }
        },
        summary_of_messages__: {
          pageMessages__: [
            {
              type: 'error',
              message: 'creation failed'
            }
          ]
        }
      }
      .
      .
      .