Trim extra spaces off pasted magnet links
Trim extra spaces off pasted magnet links

Before this change, using the "Open Torrent Address" dialog to paste a
magnet link would fail with leading or trailing spaces.

Pasting on the torrent list page has always trimmed. So this PR just
makes it consistent.

feross/webtorrent-desktop,michaelgeorgeattard/webtorrent-desktop,michaelgeorgeattard/webtorrent-desktop,feross/webtorrent-app,webtorrent/webtorrent-desktop,feross/webtorrent-desktop,feross/webtorrent-app,feross/webtorrent-desktop,webtorrent/webtorrent-desktop,webtorrent/webtorrent-desktop,michaelgeorgeattard/webtorrent-desktop,feross/webtorrent-app