fix: storage not working on tvOS

[ioannisj]

💡 Motivation and Context

Closes #315

Local storage support on tvOS is limited, so we cannot use Application Support directory for storage.
Unfortunately, the permission error is only visible when running on a physical device and not on simulators.

This fix does the following:

• Use Library/Caches for file queues
• Use lower defaults on tvOS for some SDK configs like flushAt to lower the chances of missing events

tvOS only, other platforms should not be affected

💚 How did you test it?

Hasn't been fully tested since I don't have access to a physical device, but the user who reported this verified that switching to Library/Caches fixed the issue.

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

[marandaneto]

left a few suggestions and one point to discuss otherwise LGTM