remove deserialization annotation from the exception.

Unsupported media-types only occure on the systems boundaries, no reason to carry it through the cluster and therefore deserialization not required

Signed-off-by: Joel Bartelheimer <joel.bartelheimer@bosch.io>

model/base/src/main/java/org/eclipse/ditto/model/base/exceptions/UnsupportedMediaTypeException.java

@@ -27,7 +27,6 @@
   * Thrown if a request with an unsupported media-type is made.
   */
  @Immutable
- @JsonParsableException(errorCode = UnsupportedMediaTypeException.ERROR_CODE)
  public final class UnsupportedMediaTypeException extends DittoRuntimeException {
 
      /**