Qt5, QtWebChannel, QtWebEngine: set some configs enforcing

These are passing.  Make sure they stay that way.

Change-Id: I9e1e6105f3037f0bee6e1cdbd16f7b78b737b970
Reviewed-by: Sergio Ahumada <sahumada@texla.cl>
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>