fix: update TrackingExporter test to use SpanBatch API

The batchspanprocessor_sync_ignores_max_concurrent_exports test was
added on main after this branch diverged and used the old Vec<SpanData>
signature. Updated to use SpanBatch<'_> to match the new trait.

Author: bryantbiggs

opentelemetry-sdk/src/trace/span_processor.rs

@@ -1366,7 +1366,7 @@ mod tests {
         }
 
         impl SpanExporter for TrackingExporter {
-            async fn export(&self, _batch: Vec<SpanData>) -> OTelSdkResult {
+            async fn export(&self, _batch: SpanBatch<'_>) -> OTelSdkResult {
                 self.export_calls.fetch_add(1, Ordering::SeqCst);
                 let inflight = self.active.fetch_add(1, Ordering::SeqCst) + 1;
                 self.max_inflight.fetch_max(inflight, Ordering::SeqCst);