Apply suggestions from code review

Author: trask

aws-xray/src/main/java/io/opentelemetry/contrib/awsxray/AwsMetricAttributesSpanExporter.java

@@ -30,7 +30,7 @@
  * attributes.
  */
 @Immutable
-public final class AwsMetricAttributesSpanExporter implements SpanExporter {
+public class AwsMetricAttributesSpanExporter implements SpanExporter {
 
   private final SpanExporter delegate;
   private final MetricAttributeGenerator generator;

aws-xray/src/main/java/io/opentelemetry/contrib/awsxray/AwsMetricAttributesSpanExporterBuilder.java

@@ -11,7 +11,7 @@
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
 
-public final class AwsMetricAttributesSpanExporterBuilder {
+public class AwsMetricAttributesSpanExporterBuilder {
 
   // Defaults
   private static final MetricAttributeGenerator DEFAULT_GENERATOR =

aws-xray/src/main/java/io/opentelemetry/contrib/awsxray/AwsXrayRemoteSamplerProvider.java

@@ -15,7 +15,7 @@
 import java.util.Map;
 
 @AutoService(ConfigurableSamplerProvider.class)
-public final class AwsXrayRemoteSamplerProvider implements ConfigurableSamplerProvider {
+public class AwsXrayRemoteSamplerProvider implements ConfigurableSamplerProvider {
 
   @Override
   public Sampler createSampler(ConfigProperties config) {