examples: Version bump Tor browser in download-manager

Version 14.0.4 of Tor browser is no longer accessible, bumping to latest version 14.0.7. Also fixes typo, and checks if file already exists as early as possible.

requested review from @opara

approved this merge request

enabled an automatic merge when all merge checks for 1d2b17d3 pass

Thanks!

merged

mentioned in commit 1c637909