Correct an errant null_adapter reference

Author: aarongreig

source/loader/ur_adapter_registry.hpp

@@ -123,7 +123,7 @@ class AdapterRegistry {
     };
 
     static constexpr const char *mockAdapterName =
-        MAKE_LIBRARY_NAME("ur_adapter_null", "0");
+        MAKE_LIBRARY_NAME("ur_adapter_mock", "0");
 
     std::optional<std::vector<fs::path>> getEnvAdapterSearchPaths() {
         std::optional<std::vector<std::string>> pathStringsOpt;