Dialog Overlay Issues

[andiesm813]

There are 2 issues in the dialog component:

• Angular issue: the backdrop color is incorrect. The dialog backdrop should look like the one in WC. Technically they are both using the same color, but something is happening in Angular, and it's not showing the same color as in WC.

• Dialog z-index inconsistency: in the Angular repo, the Angular dialog opens above all elements. The WC dialog opens above all elements, but the backdrop is shown behind the nav drawer. Is this expected?

@simeonoff I've reported the backdrop bug because Svilen clarified here that it was an issue indeed.
Regaring the z-index inconsistencies, maybe it's not a bug... and it only happens in the samples. But it was good to mention it anyways.

[sdimchevski]

@SisIvanova Fluent: Light theme - light/grays.500 with 54% opacity, Dark theme - dark/grays.500 with 54% opacity