Enable "Download scenery automatically" by default in launcher

Currently the launcher disables the "Download scenery automatically" option by default. This is bad for user experience, because as soon as a new user tries to select an airport other than the default, they spawn in the ocean and experience the infamous "terrasunk" issue. This is an address that comes up with new users extremely frequently on the community Discord. See also website#8 (closed).

This should be as simple as changing this line of code from:

<enabled type="bool" userarchive="y">false</enabled>

to:

<enabled type="bool" userarchive="y">true</enabled>

So for any new / prospective contributors out there, this would be a perfect first-time issue.