ref(metrics): Remove unused no-op batch processor

Remove the internal no-op batch processor now that SentryClient always
creates the configured Metrics processor and no SDK path selects the stub.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: adinauer

sentry/api/sentry.api

@@ -5678,13 +5678,6 @@ public final class io/sentry/metrics/NoOpMetricsApi : io/sentry/metrics/IMetrics
 	public static fun getInstance ()Lio/sentry/metrics/NoOpMetricsApi;
 }
 
-public final class io/sentry/metrics/NoOpMetricsBatchProcessor : io/sentry/metrics/IMetricsBatchProcessor {
-	public fun add (Lio/sentry/SentryMetricsEvent;)V
-	public fun close (Z)V
-	public fun flush (J)V
-	public static fun getInstance ()Lio/sentry/metrics/NoOpMetricsBatchProcessor;
-}
-
 public final class io/sentry/metrics/SentryMetricsParameters {
 	public fun <init> ()V
 	public static fun create (Lio/sentry/SentryAttributes;)Lio/sentry/metrics/SentryMetricsParameters;