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/infinite-scroll-content/infinite-scroll-content.tsx

@@ -1,7 +1,6 @@
 import { Component, ComponentInterface, Prop } from '@stencil/core';
 
 import { Config, Mode, SpinnerTypes } from '../../interface';
-import { createThemedClasses } from '../../utils/theme';
 
 @Component({
   tag: 'ion-infinite-scroll-content',
@@ -37,7 +36,12 @@ export class InfiniteScrollContent implements ComponentInterface {
 
   hostData() {
     return {
-      class: createThemedClasses(this.mode, 'infinite-scroll-content')
+      class: {
+        [`${this.mode}`]: true,
+
+        // Used internally for styling
+        [`infinite-scroll-content-${this.mode}`]: true
+      }
     };
   }