Inconsistency when selecting minimum Qt version

1. Start the wizard for creating a new "Qt Quick Application".
2. Proceed to the "Details" page.
   In the combo box, you can select a minimum Qt version. The items in the list are "6.2", "6.4" and "6.5".
3. Cancel the wizard.
4. Start the wizard for creating a new "Qt Quick Application (compat)".
5. Proceed to the "Details" page.
   In the combo box, you can select a minimum Qt version. The items in the list are "Qt 5.12", "Qt 5.13" and so forth.

Please refer to Qt versions with or without "Qt" consistently.

Found when updating Squish test tst_create_proj_wizard.