[BUG] Posting A SubmodelElement To SubmodelService Does Not Return A Body In The Response

[geso02]

According to the OpenAPI documentation, posting a submodel element should return the element again. However, the current implementation returns an empty body.

To Reproduce Steps to reproduce the behavior:

1. Set up a submodel service instance
2. Do a HTTP POST to /submodel/submodel-elements with a new element as body

Expected behavior The response should return the element.

• BaSyx Version [v2.0]
• BaSyx SDK [ Java]
• AAS Version [DotAAS V3]

Used Asset Administration files (.aasx/.json/.xml)

 {
    "modelType" : "Property",
    "value" : "111",
    "idShort" : "test"
  } 

System (please complete the following information):

• OS: [Docker running on Windows]
• CPU architecture: [x86]