instantiate lazily to avoid errors during startup

azure-logging/src/main/java/io/micronaut/azure/logging/AzureJsonFormatter.java

@@ -30,10 +30,13 @@
 @Internal
 public class AzureJsonFormatter implements JsonFormatter {
 
-    private final ObjectMapper objectMapper = ObjectMapper.getDefault();
+    private ObjectMapper objectMapper;
 
     @Override
     public String toJsonString(Map map) throws IOException {
+        if (objectMapper == null) {
+            objectMapper = ObjectMapper.getDefault();
+        }
         return objectMapper.writeValueAsString(map);
     }
 }