LPS-37616 Made site template combos' working consistent as underlying DB...

... indexes now makes it possible to use the same template for both public and private pages
[TECHNICAL SUPPORT] LPS-37616 Inconsistent behavior with site creation from site templates

Hi @ealonso, @epgarcia,

This issue was discovered during fixing another issue. The basic story is that formerly our DB index didn't allow to use the same template for public and private pages. It has been changed - the behavior became different when selecting the same template for both public and private pages or just for one of them at a time.

Thanks,
Gábor