APPT-1671: remove if statement for cancel booking parse (#1180)

# Description

Resolving error in the cancel booking parsing -
`{"Level":"Error","MessageTemplate":"Specified method is not
supported.","RenderedMessage":"Specified method is not
supported.","Exception":"System.NotSupportedException: Specified method
is not supported.\r\n at
Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpRequestStream.get_Length()\r\n
at
Nhs.Appointments.Api.Functions.CancelBookingFunction.ReadRequestAsync(HttpRequest
req) in
/home/vsts/work/1/s/src/api/Nhs.Appointments.Api/Functions/CancelBookingFunction.cs:line
109\r\n at
Nhs.Appointments.Api.Functions.BaseApiFunction`2.RunAsync(HttpRequest
req)","TraceId":"288a641dfb98b44e7d25fdc931a440de","SpanId":"4ffc4d12300d0c4f","Properties":{"SourceContext":"Nhs.Appointments.Api.Functions.CancelBookingFunction","AzureFunctions_InvocationId":"391bae1f-c9ab-4a7c-a067-9c7077b58400","AzureFunctions_FunctionName":"CancelBookingFunction"}}`

Example error is in 2.8 - will need cherry-picking 
index="mya_nhsuk_int"| spath TraceId | search
TraceId=288a641dfb98b44e7d25fdc931a440de

Fixes # (issue)

# Checklist:

- [x] My work is behind a feature toggle (if appropriate)
- [x] If my work is behind a feature toggle, I've added a full suite of
tests for both the ON and OFF state
- [x] The ticket number is in the Pull Request title, with format
"APPT-XXX: My Title Here"
- [x] I have ran npm tsc / lint (in the future these will be ran
automatically)
- [x] My code generates no new .NET warnings (in the future these will
be treated as errors)
- [x] If I've added a new Function, it is disabled in all but one of the
terraform groups (e.g. http_functions)
- [x] If I've added a new Function, it has both unit and integration
tests. Any request body validators have unit tests also
- [x] If I've made UI changes, I've added appropriate Playwright and
Jest tests
- [x] If I've added/updated an end-point, I've added the appropriate
annotations and tested the Swagger documentation reflects the change

Author: pata9

src/api/Nhs.Appointments.Api/Functions/HttpFunctions/CancelBookingFunction.cs

@@ -107,24 +107,20 @@ protected override async Task<ApiResult<CancelBookingResponse>> HandleRequest(Ca
         }
 
         var cancellationReason = CancellationReason.CancelledByCitizen;
-        object additionalData = null;
-        if (req.Body.Length > 0)
-        {
-            var (errorsFromBody, payload) = await JsonRequestReader.ReadRequestAsync<CancelBookingRequest>(req.Body, true);
-            errors.AddRange(errorsFromBody);
-
-            if (errors.Any(x => x.Property == "cancellationReason"))
-            {
-                return (errors, null);
-            }
+        var (errorsFromBody, payload) = await JsonRequestReader.ReadRequestAsync<CancelBookingRequest>(req.Body);
 
-            if (payload?.cancellationReason != null)
-            {
-                cancellationReason = (CancellationReason)payload.cancellationReason;
-            }
-
-            additionalData = payload?.additionalData;
+        errors.AddRange(errorsFromBody);
+        
+        if (errors.Count != 0)
+        {
+            return (errors, new CancelBookingRequest(bookingReference, site, cancellationReason, null));
         }
+        if (payload?.cancellationReason != null)
+        {
+            cancellationReason = (CancellationReason)payload.cancellationReason;
+        }
+
+        var additionalData = payload?.additionalData;
 
         var requestModel = new CancelBookingRequest(bookingReference, site, cancellationReason, additionalData);
 

tests/Nhs.Appointments.Api.Integration/Scenarios/Booking/Cancel/Autocancellation.feature

@@ -1,5 +1,19 @@
 Feature: Appointment cancellation
 
+  Scenario: Can cancel a booking when I provide no details for cancellation reason or additional data
+    Given the following sessions
+      | Date     | From  | Until | Services  | Slot Length | Capacity |
+      | Tomorrow | 09:00 | 12:00 | RSV:Adult | 10          | 1        |
+    And the following bookings exist
+      | Reference | Booking Type |
+      | 1         | Confirmed    |
+    When I cancel the following bookings
+      | Reference |
+      | 1         |
+    Then the following bookings are now in the following state
+      | Reference | Status    | Cancellation reason |
+      | 1         | Cancelled | CancelledByCitizen  |
+      
   Scenario: Can set additional data when cancelling a booking and providing no site parameter
     Given the following sessions
       | Date     | From  | Until | Services  | Slot Length | Capacity |