Update performance-metrics.mdx (#5613)

Typo

Author: artem-tarasenko

src/platforms/common/performance/instrumentation/performance-metrics.mdx

@@ -41,7 +41,7 @@ Sentry's SDKs support sending performance metrics data to Sentry. These are nume
 
 <Note>
 
-Although you can set custom metrics in the SDK, the ability to see the data generated by these metrics is is available only if you're in the Early Adopter program. Features available to Early Adopters are still in-progress and may have bugs. We recognize the irony. If you’re interested in being an Early Adopter, you can turn your organization’s Early Adopter status on/off in General Settings. This will affect all users in your organization and can be turned back off just as easily.
+Although you can set custom metrics in the SDK, the ability to see the data generated by these metrics is available only if you're in the Early Adopter program. Features available to Early Adopters are still in-progress and may have bugs. We recognize the irony. If you’re interested in being an Early Adopter, you can turn your organization’s Early Adopter status on/off in General Settings. This will affect all users in your organization and can be turned back off just as easily.
 
 </Note>