Add explanatory comment for Awaitility wait in LiveMetrics test

Co-authored-by: trask <218610+trask@users.noreply.github.com>

Author: Copilot

smoke-tests/apps/LiveMetrics/src/smokeTest/java/com/microsoft/applicationinsights/smoketest/LiveMetricsTest.java

@@ -51,6 +51,7 @@ void testTelemetryDataFlow() throws java.lang.Exception {
     assertThat(testing.mockedIngestion.isPingReceived()).isTrue();
 
     // Wait for all telemetry to be available in LiveMetrics post bodies
+    // Need to wait because some but not all the telemetry may be available in the first post body
     Awaitility.await()
         .atMost(Duration.ofSeconds(30))
         .until(() -> {