Add troubleshooting for Apple dSYMs

[philipphofmann]

Core or SDK?

Platform/SDK

Which part? Which one?

Apple

Description

The uploading dSYMs page for Apple doesn't explain what to do when Sentry shows an error that dSYMS are missing, such as the following.

Suggested Solution

Add some suggestions on what users can do to fix the problem, such as using sentry-cli debug-files find to find the missing symbols on a local machine, as pointed out in https://github.com/getsentry/sentry/issues/47323#issuecomment-1520160256.

[LeonardoRosaa]

It would be very nice!