Update dream settings UX to match latest mocks.

Updates:
- removed individual complication toggle
- added single toggle which enables/disables all supported complications
- updated colors to match mocks
- updated grid padding in order to line up with existing content. Note:
  this required more complex padding logic, using an item decorator to
  apply the padding only to inner grid elements.
- updated preview image, removing view nesting to make better use of
  ConstraintLayout
- Updated some strings to match mocks

Test: locally on device
Bug: 217555053
Change-Id: I573e5f4ed807cbe2ae9e00f183d402e6e3339590

src/com/android/settings/dream/DreamAdapter.java

@@ -70,6 +70,7 @@ public class DreamAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
             if (previewImage != null) {
                 mPreviewView.setVisibility(View.VISIBLE);
                 mPreviewView.setImageDrawable(previewImage);
+                mPreviewView.setClipToOutline(true);
             } else {
                 mPreviewView.setVisibility(View.GONE);
             }