Don't allow additon of template settings when the template is in Not-Ready state

### problem

Don't allow addition of template settings when the template is in Not-Ready state

### versions

ACS 4.22

### The steps to reproduce the bug

1. Login to cloudstack with a admin role

Navigate Images > Template > Register a template > enable “Read Instance settings from OVA”

2. When the template is getting downloaded , its in Not ready state

3. Navigate to template settings and try to add Template settings

4. The template settings gets added

### What to do about it?

CloudStack should thrown exception saying that its unable to add settings when the template is in not-ready state or Settings are read directly from the template

Reproduce el problema a través de Images > Template > Registra una plantilla con “Read Instance settings from OVA” habilitado y luego intenta añadir ajustes de plantilla mientras la plantilla está Not-Ready. Rastrea el punto de entrada de los ajustes de plantilla y su validación, y verifica que la operación se rechaza con una excepción o un mensaje en lugar de añadir ajustes.

Escrito por el modelo de indexación a partir del texto del issue.