Refactor DeviceMeasurementValidJsonTest

Simplified the test case in DeviceMeasurementValidJsonTest. Instead of checking for specific values, the test now simply verifies that no exception is thrown when the JSON is parsed. This makes the test less rigid and more focused on the essential operation.

src/test/java/de/app/fivegla/fiware/api/DeviceMeasurementValidJsonTest.java

@@ -15,7 +15,7 @@
 class DeviceMeasurementValidJsonTest {
 
     @Test
-    void givenDeviceMeasurement_WhenCreatingJson_ThenTheResultShouldBeValidJson() throws Exception {
+    void givenDeviceMeasurement_WhenCreatingJson_ThenTheResultShouldBeValidJson() {
         var deviceMeasurementAsJson = new DeviceMeasurement(
                 UUID.randomUUID().toString(),
                 "SENTEK_SENSOR",