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/grid/grid.tsx

@@ -1,11 +1,14 @@
 import { Component, ComponentInterface, Prop } from '@stencil/core';
 
+import { Mode } from '../../interface';
+
 @Component({
   tag: 'ion-grid',
   styleUrl: 'grid.scss',
   shadow: true
 })
 export class Grid implements ComponentInterface {
+  mode!: Mode;
 
   /**
    * If `true`, the grid will have a fixed width based on the screen size.
@@ -15,6 +18,7 @@ export class Grid implements ComponentInterface {
   hostData() {
     return {
       class: {
+        [`${this.mode}`]: true,
         'grid-fixed': this.fixed
       }
     };