Project Style sheet is not added to the root of the application when none of the defined project-styles are used.

[JayaKrishnaNamburu]

This is related to #529, in #529 we were trying to solve the issue with project-style sheet is not being added if the global style sheet has only tokens defined and not styleSetDefinitions.

But, currently the style sheet is not added when the styleSetDefinitions as defined but not used anywhere in the project. If the global style is not used anywhere in the project then the style sheet is not imported anywhere and thus we loose the css-variables that are defined.

Should we need to add the global style-sheet to the root of the application by default. Irrespective of the no.of style defined/used.