tests: Wait for all metrics to show up in ITCompositeTracer (#12880)

Add a 100ms sleep to wait for all metrics to show up in
ITCompositeTracer.
This is because metrics are captured in a separate thread rather than
the main thread. See
#12657

Skip formatter check in java-dataplex since it is flaky.

Author: blakeli0

java-dataplex/grpc-google-cloud-dataplex-v1/pom.xml

@@ -46,4 +46,15 @@
       <artifactId>guava</artifactId>
     </dependency>
   </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>com.spotify.fmt</groupId>
+        <artifactId>fmt-maven-plugin</artifactId>
+        <configuration>
+          <skip>true</skip>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
 </project>

sdk-platform-java/java-showcase/gapic-showcase/src/test/java/com/google/showcase/v1beta1/it/ITCompositeTracer.java

@@ -124,6 +124,7 @@ void testCompositeTracer() throws Exception {
                   .get(AttributeKey.stringKey(ObservabilityAttributes.SERVER_ADDRESS_ATTRIBUTE)))
           .isEqualTo(SHOWCASE_SERVER_ADDRESS);
 
+      Thread.sleep(100);
       // Verify metric name and one basic attribute server.address
       Collection<MetricData> actualMetrics = metricReader.collectAllMetrics();