Fix kdeconnect URL and add multi-arch support to the formula

This PR fixes the URL in the kdeconnect Cask and enables support for installing ARM builds.

Currently, any operation that evaluates this cask (like brew uninstall kdeconnect) fails with this error:

Error: Failed to open TCP connection to binary-factory.kde.org:443 (getaddrinfo: nodename nor servname provided, or not known)