Do not handle click events on dock clients because they are not managed
windows. Dock clients are responsible for sending the message to i3 to
focus a workspace if that is appropriate. i3bar now sends the message to
focus the correct workspace when that is appropriate.
Otherwise, it could interfere with the dock clients own click handling,
which could be an action to focus a different workspace than i3 had
assumed, such as would be the case with a workspace widget.