DSC-2868 fix(health): parse fetch Response body in healthCheck endpoint

The healthCheck function was migrated from axios to native fetch but
the .then() handler still sends the raw Response object instead of
the parsed body. Express serializes the opaque Response as {}.

Fix: call response.json() to extract the body before sending.
Also add null-safe error handling for network errors where
error.response is undefined.

Ref: DEV-2280
(cherry picked from commit 10fc4b0b7dc0e6f4456a78177382e94d63d39d7c)

Author: Alexandru Raileanu

server.ts

@@ -719,10 +719,12 @@ function healthCheck(req, res) {
   const baseUrl = `${REST_BASE_URL}${environment.actuators.endpointPath}`;
   fetch(baseUrl)
     .then((response) => {
-      res.status(response.status).send(response);
+      return response.json().then((data) => {
+        res.status(response.status).send(data);
+      });
     })
     .catch((error) => {
-      res.status(error.response.status).send({
+      res.status(error?.response?.status || 503).send({
         error: error.message,
       });
     });