fix: don't double-send standalone spans

Author: Lms24

packages/core/src/tracing/sentrySpan.ts

@@ -316,7 +316,14 @@ export class SentrySpan implements Span {
     const client = getClient();
     if (client) {
       client.emit('spanEnd', this);
-      client.emit('afterSpanEnd', this);
+      // Guarding sending standalone v1 spans as v2 streamed spans for now.
+      // Otherwise they'd be sent once as v1 spans and again as streamed spans.
+      // We'll migrate CLS and LCP spans to streamed spans in a later PR and
+      // INP spans in the next major of the SDK. At that point, we can fully remove
+      // standalone v1 spans <3
+      if (!this._isStandaloneSpan) {
+        client.emit('afterSpanEnd', this);
+      }
     }
 
     // A segment span is basically the root span of a local span tree.