docs(flutter): Document sdk size overhead (#12560)

Author: denrase

docs/platforms/dart/overhead/index.mdx

@@ -31,3 +31,7 @@ Note that increasing the max number of breadcrumbs **does not** improve performa
 ## Tracing and Performance Monitoring
 
 As stated in our <Link to="/product/performance/performance-overhead">product docs on the topic</Link>, Tracing adds some overhead, but should have minimal impact on the performance of your application. In typical scenarios, the expected overhead is less than 3% of the app's resource utilization.
+
+## SDK Size
+
+The Sentry SDK for Dart adds approximately 1-1.5 MB to an app's binary size. The exact impact depends on multiple factors, including the device architecture.

docs/platforms/flutter/overhead/index.mdx

@@ -41,3 +41,7 @@ As stated in our <Link to="/product/performance/performance-overhead">product do
 ## Profiling
 
 As stated in our <Link to="/product/explore/profiling/performance-overhead">product docs on the topic</Link>, Profiling adds some overhead, but should have minimal impact on the performance of your application. In typical scenarios, the expected overhead is less than 5% of the app's resource utilization.
+
+## SDK Size
+
+The Sentry SDK for Flutter adds approximately 1-1.5 MB to an app's binary size. The exact impact depends on multiple factors, including the device architecture.