DMP-4813 Change update metadata from OffsetDateTime to String so date…

… is in expected format

Changed the update metadata request from OffsetDateTime to a formatted string so the output is in the expected format

src/integrationTest/java/uk/gov/hmcts/darts/arm/service/ArmApiServiceIntTest.java

@@ -11,6 +11,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.test.context.bean.override.mockito.MockitoBean;
+import org.springframework.test.context.bean.override.mockito.MockitoSpyBean;
 import uk.gov.hmcts.darts.arm.client.ArmTokenClient;
 import uk.gov.hmcts.darts.arm.client.model.ArmTokenRequest;
 import uk.gov.hmcts.darts.arm.client.model.ArmTokenResponse;
@@ -75,7 +76,7 @@ class ArmApiServiceIntTest extends IntegrationBaseWithWiremock {
     @Autowired
     private ObjectMapper objectMapper;
 
-    @MockitoBean
+    @MockitoSpyBean
     private ArmDataManagementConfiguration armDataManagementConfiguration;
 
     @TempDir