fix(schematics): support basic style asset string (#10989)
fix(schematics): support basic style asset string (#10989)

From cli rc.4 to rc.5, the default format for style assets changed. This
change makes the theme addition support either format.

Fixes #10912
Jefiozie/material2,ppham27/material2,mmalerba/material2,andrewseguin/material2,DevVersion/material2,jelbourn/material2,crisbeto/material2,andrewseguin/material2,ppham27/material2,josephperrott/material2,amcdnl/material2,andrewseguin/material2,DevVersion/material2,amcdnl/material2,andrewseguin/material2,Jefiozie/material2,ppham27/material2,crisbeto/material2,angular/components,Jefiozie/material2,jelbourn/material2,josephperrott/material2,mmalerba/material2,Jefiozie/material2,jelbourn/material2,DevVersion/material2,angular/components,josephperrott/material2,andrewseguin/material2,DevVersion/material2,crisbeto/material2,mmalerba/material2,ppham27/material2,amcdnl/material2,amcdnl/material2,josephperrott/material2,mmalerba/material2,jelbourn/material2,angular/components,Jefiozie/material2,josephperrott/material2,jelbourn/material2,ppham27/material2,DevVersion/material2,amcdnl/material2,angular/components,mmalerba/material2,crisbeto/material2