fix(browser): Prevent duplicate INP spans when span streaming is enabled

Gate standalone INP (`startTrackingINP`) behind `!spanStreamingEnabled`
and gate streamed INP (`trackInpAsSpan`) behind `enableInp` so both
paths respect the user's preference and don't produce duplicate data.

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

Author: logaretm

packages/browser/src/tracing/browserTracingIntegration.ts

@@ -501,10 +501,12 @@ export const browserTracingIntegration = ((options: Partial<BrowserTracingOption
       if (spanStreamingEnabled) {
         trackLcpAsSpan(client);
         trackClsAsSpan(client);
-        trackInpAsSpan(client);
+        if (enableInp) {
+          trackInpAsSpan(client);
+        }
       }
 
-      if (enableInp) {
+      if (enableInp && !spanStreamingEnabled) {
         startTrackingINP();
       }