Bug: ContentSharer via Gmail doesn't trigger sharingFinished

We are facing an issue on develop branch, when a ContentSharer session where the user shares via Gmail doesn’t trigger the sharingFinished method on completion. Therefore any further ContentSharer session will hit the jassert (pimpl == nullptr) in startNewShare.

This issue doesn’t seem to be triggered by any other manner of finishing a ContentSharer session on Android, such as using Google Drive or cancelling.