Document limitations of scope attachments on iOS #4061

*Originally posted by @ramit-2343113 in *#4034

Attachments from the scope will be sent with any events that get created by the managed SDK but currently these don't get sent with events created by the Cocoa SDK.

1. Update the documentation:

This is probably temporary until we do (2)

• https://docs.sentry.io/platforms/dotnet/guides/maui/enriching-events/attachments/

2. Implement scope sync

• Scope sync attachments for Android, iOS and Native #5052