bug(windows): `update` property for windows update check is not set

[mcdurdin]

When installing a package alongside Keyman, update is set to 0, as expected:

keyman/windows/src/desktop/setup/Keyman.Setup.System.OnlineResourceCheck.pas

Line 52 in 35c82ea

http.Fields.Add('update', '0'); // This is probably a fresh install of a package, not an update

However, we do not currently set update to 1 for updates:

keyman/windows/src/desktop/kmshell/main/Keyman.System.RemoteUpdateCheck.pas

Lines 159 to 164 in b33fec4

	http.Fields.Add('version', ansistring(CKeymanVersionInfo.Version));
	http.Fields.Add('tier', ansistring(CKeymanVersionInfo.Tier));
	if FForce then
	http.Fields.Add('manual', '1')
	else
	http.Fields.Add('manual', '0');

A secondary issue is that we do not record statistics for this value, even when it is set. See keymanapp/api.keyman.com#323.