fix(demo): change the primary material color from green to blue

Author: AnthonyNahas

demo/src/material_theme.scss

@@ -9,7 +9,7 @@
 // Define the palettes for your theme using the Material Design palettes available in palette.scss
 // (imported above). For each palette, you can optionally specify a default, lighter, and darker
 // hue.
-$candy-app-primary: mat-palette($mat-green);
+$candy-app-primary: mat-palette($mat-blue);
 $candy-app-accent:  mat-palette($mat-deep-purple, A200, A100, A400);
 
 // The warn palette is optional (defaults to red).