fix(breadcrumb): remove flex item styling on breadcrumbs root class

The root breadcrumb class was using the `flex` property, which is only
used when the element is a flex item. The current parent item was
display block, so this was greyed out as having no effect. If an
implementation is using a flex parent, application of this property
would be up to the implementation.

Author: jawinn

components/breadcrumb/index.css

@@ -100,7 +100,6 @@
 	flex-flow: row nowrap;
 	align-items: center;
 	justify-content: flex-start;
-	flex: 1 0 0%;
 }
 
 .spectrum-Breadcrumbs-itemSeparator {