Remove 400 Bad Request response from Delete method

The `[ProducesResponseType(StatusCodes.Status400BadRequest)]`
attribute was removed from the `Delete` method in the
`OutResController` class. This change simplifies the API
response documentation, leaving only the `204 No Content`
response explicitly defined. The method is no longer expected
to return a `400 Bad Request` status code, reflecting a change
in behavior or a decision to streamline the API's response
documentation.

src/ReC.API/Controllers/OutResController.cs

@@ -65,7 +65,6 @@ public class OutResController(IMediator mediator, IConfiguration config) : Contr
     /// <returns>An empty response indicating success.</returns>
     [HttpDelete]
     [ProducesResponseType(StatusCodes.Status204NoContent)]
-    [ProducesResponseType(StatusCodes.Status400BadRequest)]
     public async Task<IActionResult> Delete([FromQuery] DeleteOutResCommand command, CancellationToken cancel)
     {
         await mediator.Send(command, cancel);