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/fab-button/fab-button.tsx

@@ -95,6 +95,7 @@ export class FabButton implements ComponentInterface {
       'aria-disabled': disabled ? 'true' : null,
       class: {
         ...createColorClasses(color),
+        [`${this.mode}`]: true,
         'fab-button-in-list': inList,
         'fab-button-translucent-in-list': inList && translucent,
         'fab-button-close-active': activated,