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/segment-button/segment-button.tsx

@@ -71,6 +71,7 @@ export class SegmentButton implements ComponentInterface {
     return {
       'aria-disabled': disabled ? 'true' : null,
       class: {
+        [`${this.mode}`]: true,
         'segment-button-has-label': hasLabel,
         'segment-button-has-icon': hasIcon,
         'segment-button-has-label-only': hasLabel && !hasIcon,