[3.20.x] Rest-openapi contractFirst: rest configuration context-path should be favored as base-path

### Bug description

In case of the OpenApi contract first implementation as
```
restConfiguration()
.apiContextPath("/api/openapi")
.contextPath("/camel")
.hostNameResolver(RestHostNameResolver.none);

rest("/camel")
.openApi()
.specification("openapi/contract.json");
```

The rest endpoint does not work as expected. (`curl http://localhost:8080/camel/${endpoint}` returns 404).

This problem does not happen on `main` branch.