fix(components): include mode classes on components for use in shadow (#17838)

- removes mode-less component classes from the internal CSS, use element instead
- adds mode specific classes `md` or `ios` for styling inside of shadow components
- adds e2e test that verifies mode classes exist on all ionic components, plus checks for specific classes that the components need for internal styling

fixes #17608

core/src/components/alert/alert.tsx

@@ -392,6 +392,7 @@ export class Alert implements ComponentInterface, OverlayInterface {
       },
       class: {
         ...getClassMap(this.cssClass),
+        [`${this.mode}`]: true,
         'alert-translucent': this.translucent
       }
     };