Don't break apps with older import versions

QML versioning works in the following way:

a) New QML element is registered with a version number where it
   was introduced. Version number for this element should not
   be changed in later releases of the library to keep apps with
   older import versions to work without a need to update import
   statements in the app.

b) For "import x.y" to work there must be at least one element
   registered for that version - x.y.

   QtQuick.Enterprise.VirtualKeyboard.Settings was introduved in 1.2

   - we can't increment version for it because that would break
     older applications (see point "a").
   - there are no new elements introduced in this namespace thus
     version for *.Settings remains 1.2.

   This is how Qt Quick Controls handle similar cases.

Change-Id: Id8f5ca572d9f1558d607dc0abfac79d41865e099
Task-number: QTRD-3576
Reviewed-by: Gatis Paeglis <gatis.paeglis@theqtcompany.com>