fix(ffi): annotate body in raw body branch

If the content type was not otherwise handled,
`OptionalBody::from(&str)` was used. This sets the content type
associated with the body to `None` irrespective of the content type
passed through to `process_body`.

This fixes the issue by ensuring the `OptionalBody::Present` is created
with the appropriate content type.

Signed-off-by: JP-Ellis <[email protected]>

rust/pact_ffi/src/mock_server/handles.rs

@@ -1730,7 +1730,11 @@ fn process_body(
         _ => {
             // We either have no content type, or an unsupported content type.
             trace!("Raw body");
-            OptionalBody::from(body)
+            if body.is_empty() {
+                OptionalBody::Empty
+            } else {
+                OptionalBody::Present(Bytes::from(body.to_owned()), content_type, None)
+            }
         }
     }
 }