fix(browser): Skip CLS/LCP measurements on pageload span when streaming

When span streaming is enabled, CLS and LCP are emitted as streamed
spans. Previously they were also recorded as measurements on the
pageload span because the flags only checked enableStandaloneClsSpans
and enableStandaloneLcpSpans, which default to undefined.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: logaretm

packages/browser/src/tracing/browserTracingIntegration.ts

@@ -434,9 +434,10 @@ export const browserTracingIntegration = ((options: Partial<BrowserTracingOption
         // This will generally always be defined here, because it is set in `setup()` of the integration
         // but technically, it is optional, so we guard here to be extra safe
         _collectWebVitals?.();
+        const spanStreamingEnabled = hasSpanStreamingEnabled(client);
         addPerformanceEntries(span, {
-          recordClsOnPageloadSpan: !enableStandaloneClsSpans,
-          recordLcpOnPageloadSpan: !enableStandaloneLcpSpans,
+          recordClsOnPageloadSpan: !spanStreamingEnabled && !enableStandaloneClsSpans,
+          recordLcpOnPageloadSpan: !spanStreamingEnabled && !enableStandaloneLcpSpans,
           ignoreResourceSpans,
           ignorePerformanceApiSpans,
         });